Thanks for sharing this, enjoyed reading through the retrobike thread. Many of the highs and lows of effing about with vintage bikes! Seems pretty standard to get your plans straight only to find something like the bottom bracket is incompatible with anything you want to do :)
The chainset did cause some problems. I had intended to use the Chater Lea set that I had on this frame in the '90's (see pic with rather grumpy looking young son on board). When I came to refit it I found that it was a poor fit on the spindle (too loose) and came so close to the chainstay I would have needed to get it almost perfectly true to prevent it from fouling on the stay. I really can't understand what's going on here, since I don't remember having this problem when I used it before. Copied from my 'Last Build' thread in Current Projects.
We all suffer from these problems. I still don't understand what happened here - I suppose it's possible that the Chater set has somehow been damaged in storage - although I can't see how this happened. Also I wonder if there could be a slight difference in the size of the spindle (not what you'd expect with CL kit). Perhaps I just tolerated the slackness - I was using a Sturmey hub so the ovality problem was less critical than it would have been with fixed.
While I'm om the subject, compare the two cranks on the scales - when you take into account another couple of ounces for the left hand Chater crank the difference makes the BSA/TA set about half a pound lighter. I know we're not too concerned with weight in this thread, but all the same, my bikes are for riding, and quite often with others on more modern machines, so I don't want to give too much away!