Yup, just tried one of the original motors on the left circuit and that doesn't reverse either, so I guess that confirms a blown transistor. What a bummer, just spent a week spraying it all up and fitting the new bits and looking forward to getting it running again!!

I will order a new board, and see if I can buy the transistors (they will be pennies) to repair the old one as a spare.

Thanks for the help and advice, much appreciated, and once it's all back together I will post some pics.

Cheers

Rob G