After the problems of the track testing and problem finding update I last put on I left it for a day or so but did have 1 or 2 comments from friends who told me to check and check and check again my wiring. Ok so I'm a numpty as when I went to check the wires I found that the positive bus wire droppers were wired to the + point on one board and I thought I had done the same on the other board but to my surprise I found that on one board I had done it to the red bus wire but on the 2nd board I had wired the same but to the black bus wire. I've crossed them wires over so I have red/black and black to red and it now works now without tripping the system. I feel like a right dunce. Anyway I went round and rechecked all my soldering of all the droppers to the track and found only 2 dodgy soldering joints which I have now fixed and it runs perfectly at all speeds.

So now red faced I'm ready to do some scenic work.