I won't get carried away,as Neil seems to be sorted, but Dunney just for the record, this was all discussed a few months ago in fair detail, and the fact that the dyno 'motors' either way is not conclusive that it's ok (I know from experience- had a dodgy armature), but simply tells whether it's wired the correct way.
If it motors faster it may be better indication of condition than slow, but someone else will be able to verify better than I.
cheers..