Just getting back on to this problem, looks like I need TIP102 Transistors and 1N4004 diodes, but is there any higher rated components I could or should use in this???

Cheers

They have worked OK for years - fitting higher rated parts will only create more smoke when there is a problem IMO.

I never bother with 1N4001/4002/4004 and only stock and use 1N4007 as they are rated at 1A 1000V and are EXACTLY the same price as all the others - I can't even work out why retailers even stock the others anymore??