The problem is... that you spent 150 quid on some coilovers.... and expected them to be good!
I'd usually agree here...you know "buy cheap, buy twice" but I've been using tuning art coilies on my last 3 cars. For the price, they're actually pretty good and come with a 3 yr warranty. They usually have a lot of adjustability in them. This is my E36 on tuningart coilies:
If u have issues, drop Edwin an email at tuningart and see what he can suggest, a nice guy and will help out if he can.