Congratulations!
Keep the flaps of the pockets closed if it rains. Even if the water doesn't enter to the body, it's pretty unpleasant to collect water in them.
As I wrote, the blue German ones are very rare. They weren't issued so long and our navy isn't so large and when they got sold to civil persons they had been sold very fast. It's the same with the green ones, not issued for long time, sold out immediatly later. The younger Flecktarn version was issued for longer times and because it's Flecktarn not everybody wants to run around in the towns with it, so they are still available in good conditions.
I guess you can find them in British surplus shops too perhaps a bit pricier in the first view but perhaps without higher shipping costs and especially the British surplus shops look through the stuff. If you can buy grade 1 it's worth to invest a bit more money. I always buy grade 1, used but in nearly unused conditions. Like that we make the best deal.
You should immediatly test such surplus rain gear under the shower at home, if the stuff is really water proof.
With your stature and age I recommend generally to buy light but long lasting stuff. You don't need to look for extremely thin and weak ultralight trekking equipment but you should keep the weight in sight if you choose to buy equipment.
If you read in old threads for example in this forum about a good pot you don't know if the guy who writes is a 25 years old 1.90 meters tall carpenter, the owner of a Canadian canoe or even of a Landrover 110. A usual well chosen trekking or bushcraft equipment contains round about 40 single pieces of equipment. If every item is only 25g heavier than necessary the result is, that your full rucksack is in the end 1 kg heavier than needed. And that difference you can feel on your back!
Don't count an unnecessary heavy summer equipment together and think, that you can carry it easily. With water and food, soap and perhaps fuel for a gas burner or alcohol stove it's suddenly quiet heavy and should you go for winter camping with additional stuff, you would realise in the end, that you invested in the wrong stuff, and that would be a pity.
Usually people realise it to late and would need to reduce 50g to 100g on every item to get the whole equipment portable, and that they only are able to do, if they buy every item ones more!
You should buy the stuff as long lasting as possible, as strong as necessary and as light as possible after it fits to the first two points. Or to say it different: Generally you should buy the lightest of the durable options, especially if you carry it always or sometimes in your rucksack. Boots for example can be different to that pretty heavy. They make your legs faster tired than light ones but that's a question of training too. A heavy rucksack stays a heavy rucksack, training helps a lot but to carry exclusively bomb proof equipment for winter camping with food and water you should train 15 hours a day with the special forces, the best directly with the foreign legion in France...
But no reason to buy a weak knife. I own the Mora Garberg in the stainless version.
I was able to shave myself with it - with an office ready result - after I sharpened it with a simple sharpening stone in farmers quality free hand. That means, the steel is a good recommendation.
The design has the charme of a German made screw driver. It's a bushcraft tool, no polished beauty. But it's a really good bushcraft tool!
It's without any doubt a very good all purpose knife but a real, nearly unbreakable survival knife as well. The handle seems to be very well attached, unbreakable in intended use. Protective in coldest conditions, different to most other strong knifes with a handle design which doesn't pay attention about extremely cold conditions.
I recommend the Mora Garberg without any doubt.
But I absolutly do NOT recommend the multi mount plastic sheath! I think it's a pretty idiotic and in deep forests really dangerous toy.
I got the Garberg with the multi mount sheath generously gifted by a member of this forum. Thank you very very much ones more! So I own it with the multi mount sheath, but I will buy the leather sheath later. My fear to loose the knife in deep forests where I perhaps could really need it is to big. And that's because the plastic sheath isn't perfectly constructed. OK for use in civilised areas, OK for use around the house. But not OK if the knife is meant as a survival knife. Who carries the Mora Garberg as all purpose knife but just in case as a survival knife too, how it is constructed, should choose the leather sheath in my opinion.
You can buy the Garberg with the leather sheath without any doubt, so far it fits well in your hand. The knife is made very long lasting. The "stainless" version in the leather sheath will not rust so easily even if the leather gets whet. The Carbone blade version would probably start to rust.
But of course also the stainless version is better kept in a dry leather sheath or a dried leather sheath and even this very very slow rusting material is better stored for longer times with a very thin film of olive oil on it if you put it away for several weeks. And the sheath likes to get several times good leather fat from all sides before it goes into the bush.
Other wood handled very good knife options with high value for money cost round about 150 €, look nicer but aren't so extemely idiot proof and tough, but I guess tough enough for use in Britain. So if the Garberg doesn't fit into your hand well, ask here about other options!
But the Garberg offers an outstanding good value for the money regarding the functionality.
(Other similar options cost 50 € more because they have a nicer and shinier finish and more expensive but probably less durable handle materials.)
In my opinion the Mora Garberg is a high end quality tool, compared to similar knifes relatively cheap because it's made industrial and not polished like a mirror. The a bit unfinished edges of the back of the blade you can easily round a bit with a few scratches of every sharpening stone. I guess you can do it at the rough uncoated bottom of a usual porcelain cup as well with a perfect result.
Don't round it too much if you want to use it with a ferrocerium rod! That's the reason why these edges are so sharp as they are.
The without any doubt functional looking Helicon tex shirt has the opposite mixture than a lot of Solognac, Austrian Army or German army clothing.
I recommended as a good spark resistant but also relatively fast drying outer layer a mix fabric with 65% cotton and 35% polyester.
The Helicon tex shirt you showed us has different to that 65% polyester. That shirt is faster drying than the shirts I recommended, it is equally windproof but it is NOT spark resistant!
Surely good for hiking in Britain and traveling in northern relatively whet conditions this shirt isn't the first choice for use around camp fires. The fire protection of this shirt is next to nothing, every spark will produce a tiny hole in my opinion which weakens the fabric. I don't know exactly that shirt or fabric but I know similar fabrics from Fjälräven and Pinewood which I do not recommend for bushcraft use around camp fires, especially not to beginners!
Yes, of course it would work pretty well for hiking and stealth camping, especially fast drying what's a good idea in Britain, but it doesn't protect against fire and sparks. It is a plastic shirt with a few cotton fibres in the fabric!