Yep, these are definitely at the cheap end of things. Chinese made I think. They might be 'ok' for a few months but... they're cheap for a reason.
The more expensive FK coilovers are German built. Still not amazing, but a solid step up from any ~£200 coilover kit.
I'd suggest the Highsports Pashka has are a better option. I think these are made in Germany? Not sure what car you're in, but like he says - lower spec is 50mm strut diameter; GTI etc is 55mm.