The general concensus is not to bother. It's so hard to get it to fit as it's 5mm longer you have to just about drop the dash out to get it in. I recommend you rip the old dash out and fit a Mk2, suprisingly easy. You can buy the lot for about £40 from a scrappy.
it can be done but as said is a lot of hassle. you have to butcher the dash and make it all fit using a mk2 cav dash surround. i tried it and it just doesn't look right. afters hours and hours of work i just scrapped it and bought a mk2 dash. nuff said.