In January last year I discovered that Wood Green had a dojo, in the Chocolate Factory. Who knew!
I have been going to an aikido class there on a Monday night ever since, a really great (female) teacher and lovely group, Her (male) partner takes the Thursday evening class.
Sadly the dojo will lose its home next year, i think, in the meantime, this is an absolute gem to be made the most of.... Excellent for kids too. Check out their website for class times http://www.northlondonaikido.org
no previous experience required, beginners are absorbed into the class (specific classes are open to beginners, others not).