Andy: I would suggest being VERY careful about handing off the bike to a young mechanic for even the crankset removal unless you are quite sure that they have the proper tool and can do it right. It is all too easy to imagine a bike shop mechanic, inexperienced with vintage bikes looking at it and thinking it's 'just another old square taper' and messing things up. Sometimes young people are a bit too confident, and their listening skills not fully developed--a bad combination.

And am I correct in reading the serial number stamped into yours as being 104345? Mine seemed to be 104315. Members here have turned up bikes that are even closer than that in SN's but that is pretty darn close!