A quick update for anybody whose interested - ccfj1 sent me a a GOOD V.32 OS disc, did the install as usual (loaded the disc even though i had no power light at all) and hey presto, 3 mins later i have fully working Sat Nav again!

To anybody having the same problems as me id suggest checking the disc youve burnt off, i thought i had mine perfect but obviously not!!!

Big thanks to ccfj1!

Stew