I only passed my test in Feb., but the instructors made it clear that they were teaching you to pass the test rather than to ride well, a sad state of affairs in itself.
Anyway I joined the Essex Advanced Motorcyclists’ Group,
http://www.eamg.org.uk/ , to get some further training -they do IAM and RoSPA. I will probably take the IAM at some point this year, but don't have to and the training is well worthwhile in itself.
Beyond that there's the social side with several ride-outs each month,.
J