Go for it but dont pay too much IMO.
Shergolds/haymans were the guitars to have in the late 70s/early 80s as the output from Fender and Gibson was not only too expensive but was questionable quality too.
Many Punk/post punk bands used them. Peter Hook and Bernard Albrecht from Joy Div and New order used them, as did bands other bands. I would jump at the chance for a Shergold myself, at the time that they were available I had to make do with Antorias, Hondos and Satellites.
I'd love an old Shergold Masquerader, or Meteor. Cracking guitars, and true innnovators too. But sadly not worth what some folks are asking for them. Good playable guitars, but not in the same league price wise as others.
Again, dont pay too much, but they are a pretty playable guitar