Sounds like a fun day out, I hate when places have different rules that don't seem to make sense.
The Dura ace BB is the smallest of all the tools, even smaller than the Ultegra/BBR60 one but it looks identical from afar.
I've had a guy come in twice now with a frame he got from Planet X during that auction thing they did.
Fit headset supplied and cut steerer - he brought a 1 1/8" external cup headset for a 1 1/8" - 1 1/2" integrated frame.
Came back today with rear gears "set up" with brake cable with no ferrule at the shifter and the inner cable clamped on the wrong part at the mech.
I can sort all of that but he had a 34.9mm clamp, I think, slid down the seat tube until it met the top tube and just horsed up tight. Supplied a 31.8mm clamp to fix that.
Front mech was also a 34.9mm but with rubber shims from a light or such to pack it out. Proper bodge. Last picky thing was the lower jockey wheel being on backwards - said has no excuse for that as it even has an arrow on it!
I think I may ride my bike again soon after 9 days off it, hope it isn't too icy in the morning.