new rider from aus

[MeiHua]

Hi,
im a rider-in-the-making out in australia on a gap year, hoping to pass my test in may and coming back to london in september,
was just wondering if there are organised rides or such like?
here in perth im on a forum called perthriders.com, its a really soical group, quite a few members meet up three or four times a week if weve got the time and ride around aimlessly. sometimes there will be around 30 bikes, sometimes only 5 or 6. maybe i was in the wrong places but i dont remember ever seeing that amount of bikes in london!!
it would be cool to meet some londoners that ride and get to know the roads differently to driving, and i will be based around croydon or canterbury (depending on uni)
any info let me know if you could,
thanks!