sced,
I agree with Wileyone number along BB edge is typical of TJ Quick's work who was the Putney Shop "specials" builder by 1973 - the year you remember frame being ordered in approx. March. (dwscrimshaw's serial prediction also predicts to early 1973.) Quick had taken over from Reg Collard on his retirement estimated to be a year or two before.
Thanks for pics clarifying that number is indeed 69559 as Dave has another shop frame with same number in his prediction data (no pic available of that serial).
https://drive.google.com/drive/folde...UZYSTNKZkN4TmM
I believe typical of the "Cronometro" - a 5 speed TT Putney Shop model. Were under bracket cable guide(s) added later? A real beauty and great job on restoration!
Doug