Hey
Sorry, I don't live in the Southampton area but like you I would also like to join a cycle club within Brighton & Hove. I'm not really a lycra kinda girl and just have a mountain bike. Some of the clubs in my area look like their really into riding (and although I love cycling am looking for a bit more of leisurely pace) so at the moment I don't feel there is a club that 'fits' at the moment.
I'm also quite shy so can appreciate some of the anxiety around this but def worth perservering and I guess the first time is always the worst. East Sussex runs a summer programme of rides that anyone can turn up too so am gonna trying a get myself on some of these to start off.
Have you tried your local library for clubs? Your local council wesbite may also have further info about the ones in your area.
Failing that I'm sure someone more local to you will have some ideas.
powla shame were not closer as you sound like me not really wanting to get into the lycra or racing thing i love riding my bike always have good job i do as i cant drive
and agree the first time will always be the worst i want to find a club that is not a racing club but are encouraging if you want to train for an event so to speak like my wanting to do the 118 miler