I had a ukpk for maybe two days from a trade with (welchyd) from here.
I fileworked the spacer and got shot it was horrible to hold and to be quite frank felt cheap and nasty.
It's worth bearing in mind that not all UKPKs are made equal.
The original came with G10 scales and S30v blade
There is a version with Titanium scales and S30v which is the expensive version.
There is a version with FRN scales and Gin 1 blade or CTS-BD1 blade which is the budge version - that was the version you had so yes, it was the cheap one. Nasty is quite a statement. Many people don't like FRN because it feels lightweight and fragile but in reality it's very very tough stuff. I would be impressed if someone broke one in normal use.
I love knives - all knives - except a few that are really bad The UKPK is really bad - dreadful lockup, uncomfortable handle with square edges that causes hotspots in a nano second, silly blade design that is too wide to pass under tight packing tapes. Hate it - it languishes in a drawer somewhere.