Thanks for your help everyone, I have now completed the chassis and it is working well with a TCS T1. In the end I built the chassis exactly as the instructions advised only I increased the distance between the wheels and the brake shoes slightly and added small amounts of plasticard to the insulated wheel side. Everything seems to be working happily with no booster shuts down as yet. I really should have mentioned that although new to kit building loco, I have been using DCC for 5 years or so now, and despite the poor wording in my original post, I do know the difference between trackside and motor side shorts. The main problem with DCC for the masses has to be the language barrier! Although being a mechanical and electrical engineer, I'm off to the corner to hang my head in shame...
Thanks again,
Rob