Depends how early you want to start really and how far you want to travel!!!
End of February if you want to start early is the Redhill Sporting that starts and finishes just outside Dorking. . It's about 15/18miles long depending I think. Sporting means there are hills in it
A couple of weeks after that, one of my favourites is the East Surrey Hardriders, just under 30 miles long. You usually get some good names riding. Starts and uses on the some of the roads that the clubrun uses but also goes down the A24 to just outside Horsham and back round. There is a stinker of a hill on the way back. Really enjoyable, one of my early season aims this year is to try and crash the top 10.
After that you have some Southern Counties events which are also good fun then you really from about April start on the faster courses. If sporting courses are your thing they are on during the year if you are prepared to travel eg Rudy Project and Jon and Mr G try the ECCA SPOCO.
Get a hand book from Jon when the order comes in or bump this nearer the time and I am sure I/we can sort you out some races.
Looking forward to it already and it's only December