I have to say that with standard cone drivered speakers that the 60/70's seem to be a time when engineering was amazing and the build quality very high.
Turntables of that era also appear to be very well engineered.
I have personal reservations of the age of electronics - so when it comes to Electrostatic speakers factor in that most will need work - If they dont thats good, but at that age a service is well worth doing.
Electronics in valve amps - though most are basic - and thats the good part of the design, transformers can start to buzz as the core leafs separate, capacitors dry out. I sold all my valve amps some time ago - I will consider valve again but NOT the new imported rubbish !!! the old stuff is still made the best.
For speakers I am still looking for a pair of B&W DM70, I feel those might give my Tannoys a run for the money - But I have never heard them side by side - To date all pairs I have seen/heard have been in need of serious repair mainly to the electrostatic section and the usual bass rubber.
Sansui equipment of this era is often mentioned - ever seen the older range of speakers !!! they are serious furniture.
Early Acoustic Research Cambridge speaker AR series are very good - again these usually need a refurb on the rubber edge - I do this work so thats not bother for me
.
What I would say is be VERY careful of people who have done the refoam work themselves - usually you can tell as the g
lue line is all over the place, the driver ends up off center and to be honest a decent speaker ruined. I prefer to buy with damaged edge and rework correctly.
UK built stuff by bill beard is well made - I have worked on four beard units (pre and power)
Are you looking to stay with UK designed / built items ???