I just assumed the popularity of
Georgia was due to the popularity of
George which also became very popular in the '90s (and has always been used anyway due to royal connections and
George being the patron saint of England).
Georgia Taylor may have had some influence, in that she was in Coronation Street which is the most popular TV show in Britain (and was in the '90s) and the soaps are always featured in the papers and magazines.
The name
Georgina was well known, maybe people got bored of that and just wanted an alternative to that and then
Georgia really took off? I hadn't thought about it until now, I must admit.