Quick update on this....... Stripped all apart today and the problem lies with the new crankshaft oil seal that sits behind the flywheel..... it would appear that the metal used to make it is to thin, about 1mm. Thusly meaning the flywheel bolted back to tight against the crankcase. I bought it off eBay for 35 quid so I would say its a bad case of buy cheap buy twice. Going to speak to Chrysler on Monday and see what a genuine part will set me back. Will keep you posted