Thanks for posting the number, Serial number photos are great, your number is clear but some are badly stamped and are often open to more than one interpretation. The early CWC frames like yours have been found so far with either an “X”, a “Z”, or an “A” followed by four or five numbers.
My interpretation is that the X and Z frames are earlier than the A frames and that the A frames are solidly 1936 production. I have A21423, A52260, and A81332 currently in the database, The first two are essentially identical to your bike and the last is later model normally associated with 1937+ production but it still wears the 1936 chainring.
Anyway, good luck with your build, I’m considering doing a bike for this build-off as I got to the site too late for the last one. I’ll mull it over and see if I can decide on a frame and find the time to get something going.
And thanks again for the number and photo.
Phil