Not really possible in my part of the world. London just doesn't have a decent stock of new or second hand ST books anyway, even Forbidden Planet is starting to reduce their stock. The only place I might find them is in my local secondhand sci fi and fantasy bookshop, but even that is unlikely, they tend to stock more of the TOS and TNG than any of the others.
I find it really hard to believe that London (and suburbs) has less second hand bookstores than Sydney. (While our second hand stores have slowly vanished, especially from the CBD, I still know about four with huge ST sections.)
A lot of second hand sellers have gone exclusively online these days. Sure, some ST novels are perceived as "rare" ("Mission: Gamma #1" before the recent tpb reprint) and command high prices, but I'm sure most Stargazer titles would be quite reasonable online. And online searching is so efficient!