Previous experience and sight-reading ability are obviously beneficial, but are by no means pre-requisite.
The best time to join is immediately following a concert, when rehearsals begin for the next one. The next good time would be Wednesday 14th December, after the carols. Or even 23rd November, if your knowledge of the carol repertoire is pretty good.
After you have attended two or three rehearsals, there is a short, informal audition. This is mainly to check you are singing the right voice part. It is not something to get greatly stressed about!
All voices are welcome, but if you are a first soprano or a tenor you will be even more welcome!
You can ring Madeleine on 01704 568496, or send an email from the contact page