Hi Nlerner, this is exactly the kind advice I need and thank you so mush for taking the time to write. My knowledge of bikes is of those older than 1980 so anything you can tell me about this charming frame and its potential to be brought into a semi-current spec would be most gratefully received.

For the wheels, I measure 127mm rear (maybe a little bent), 99mm front (should be 100mm?). I would, as you suggest, definitely want to try a cassette as all my experience is with freewheels so that would be something new for me. I'm not sure how I can find a wheelset that would fit the older spacing but take a cassette! The derailleurs would be my other concern (the machine has downtube shifters), as I have a nice set of Dia-Compe side-pulls from a donor bike, and can probably find some aero levers somewhere, and the contact points should not be a challenge. I do have Suntour AR F/R derailleurs and a Sugino VT crankset that have seen very little service if this might not result in too much of a mongrel . . .