I think that they are nearly all listed in Pooleys on in the list of glider launch sites.
Which shows name, elevation, lat/long, and operating height. No other information. Even a contact phone number would be a huge improvement.
Why does all you say apparently not apply, say, to Aylesbury Thame - a winch launching glider site and busy club with no powered facilities who nonetheless seem happy to welcome powered aircraft and publish procedures for them? Is there something wrong with the place?
For that matter, should I stop flying at Booker now? With a two powered runways, helicopter operations, AND a gliding club regularly taking off and landing in different places, it's clearly a deathtrap and somehow I failed to appreciate that the local procedures to stop us all flying into each other, are totally inadequate.
G