The fault is obviously over riding your starter solinoid, therefore it has a relay ahead of that. It might be what the previous posted said. the clue will be the 'motor e brake' light. will be nice to see if any of the other bluebird guys will tell you...
you can always join the busconversions. com forum, and ask those guys as several are real experts....
course, if it were mine, i would probably end up bypassing the relay... i did that on several of them on my thomas...