Was the other aircraft the only other circuit traffic? If so I think i would have asked for a left base join on initial contact. If that was refused, then i would have made a standard overhead join, at 1500'QFE, assuming a 1000' circuit. Descend dead side with a 180 left turn onto cross wind. I find its much easier to slot in with circuit traffic this way, and if the base call was refused then there must have been traffic? As far as the definition of the down wind leg goes, i think it starts at 45 degrees to the up-wind threshold? I hope in all the fuss and confusion you didnt forget to do a full BUMPFITCCH? Including a good long blast of carb heat?