ah well, circlip is last of my problems now. I fitted the new fet tonight, but, didn't realise that the screw holding the heatsink had to line up, so then had to remove the new fet and fit the spare. Whilst getting it off, I "could" have damaged the board, really don't know, because when I powered it up with a test light, all was well for a few minutes, then one leg of the fet sparked, and that was the end of that .
I possibley (likely) need a motor, and now need a board, its really not worth it, too expensive, and the board is out of stock anyway at the only place with one, arc euro trade.
I have to call it a day, and will consider selling the machine for parts/spares. Buying both parts is the only way I will be sure that its fixed, luckily the board was not fitted back inside the case when I did the test, otherwise I would not have seen the fet sparking.
I need to pack it up, and think long and hard, almost £200 to get it working again, I bet the machine isn't worth much more than that.
Many thanks to all that contributed

!!