As an Irish dancer and musician one thing I realised after I moved to London was that I was actually really far from the focus area for Irish music and dance. I was so disappointed to discover that it would take me the best part of 2 hours to reach a session and could take even longer to get back if I missed the last tube. The world righted itself in this respect when I saw an appeal on Facebook last June for a new music teacher in my nearest Irish centre, which is undergoing a revival of it's cultural programme. I am now back teaching Irish music and am so happy at seeing the enthusiastic 2nd/3rd generation Irish learning their culture. I have also gone back to Irish dancing at the centre. As a non championship dancer I found it really difficult to find a dance school that would take me but I love my new dance school and the teacher is even letting me work with some of the younger dancers to perfect some of their technique (TCRG qualification here I come!!) and the classes are on a Saturday morning!
For all you GAA die hards remaining part of a football/hurling/camogie team can be harder than imagined. Most teams are based, like the music, in North West London but teams do exist in other parts of London as well. If you are a GAA Scór enthusiast the good news is London can compete in Scór, the same as they do in football/hurling (compete in Connacht). The bad news is that it is not done so unless you are willing to revive it, you could have some difficulty in competing.
All other hobbies/interests are easy enough to find and once you have good transport links everything is accessible, some journeys just take longer than others.