Hi - I was fiddler in Meet on the Ledge for a number of years - joined just after they recorded Mary Stanford.
That is the email address I have - I haven’t been in touch with Allen for a long time but I believe he has a website selling his books. Worth a google.
If you don’t manage to track him down, I think the royalties from this particular song were donated to the RNLI - may be wrong though.
Hope that helps!