haven't had time to get hold of springs or a dremel yet but managed to get a coil pack which i put in last night.
was slightly different to my others and the plug didn't quite fit properly, managed to rejig it and connect it but it still sounds like a wrex
so i've pulled it out again.
no idea why it didn't work, perhaps due to it not fitting correctly.
i think now i'll just get someone out to look at it, don't want to do more harm than good.