A good guidebook is, really, all about the homework. That's what gives the authors the credentials to be taken seriously; the painstaking hours of research, of walking the walk, of going, doing, seeing and living the thing you want to tell others about.
Janet, in particular, has been grafting at this for a long time.
Since at least 1973, it seems, when she was so looking forward to a holiday visit to Stonehaven outdoor pool that it warranted a mention in her journal.
So you can rest assured that a LOT of homework has gone into the Lido Guide.
Credentials, innit.