Well, I did it.
It worked absolutely fine. Well, for what I wanted it for - to make a sleeve for a windshield.
Not sure it was the most cost-effective way (two chamois from Morrisons at £3.50 each, then some leather laces at another couple of quid, and then a bottle of suede dye - which I already had but could have been another fiver or so), to be honest. But then, what with lockdown, all the charity shops have been closed so I couldn't scout them out to see if they had any suitable leather items for cutting up (and even now they've opened I'm not sure I can be bothered to go into town and go into all the shops for something so trivial and unnecessary just on the off chance).
Anyway, here's the results...