This annoys me a bit too. I'm in the midlands but it's a bit of a pain when 99% of the events seem to be down south. Like, really down south. Your best bet might be Robots Live in Grantham or Cannock (perhaps next year along with Manchester for Extreme Robots). These are heavyweight events, but they also do featherweight rumbles, so there's plenty of action for them too.

The Insomnia 61 gaming convention is at Birmingham, hopefully Robochallenge's featherweight championship is happening then (not confirmed yet). I know all this is still fairly southern compared to Glasgow, but at least it's not London.