I think many of the agencies in Yorkshire are attached to part-time stage schools and attending lessons there is one of the requirements of being with the agency. we know people who are with or have been with: Scala in Leeds, they've had lots of success with stage, TV and film work there's also Rebel (in Leeds) Northern Film and Drama (Castleford I think) and Stage 84 (outside Bradford) and Tonicha Wade (ex Emmerdale) has started an agency and stage school in Collingham outside Wetherby, I think all of them have had people on Emmerdale, Waterloo Road and Yorkshire filmed BBC/ITV series like Marchlands, South Riding etc.
I also heard that the Mark Jermin agency were recently looking for Northern talent...
So I suppose it depends on where you are, what you're looking for and whether you're happy to pay for lessons at a new school

Hope that helps!