In reply to Ryan_ID:
Being in Essex is ideal. You're perfectly placed for reaching much rock.
None of this only climbing on one crag or rock type for you.
Closest real rock is sandstone.
Lead climbing you're just about equidistant (in time) from Dorset limestone, Bristol area limestone, Peak grit and peak limestone.
If you have a whole weekend to spare, Devon, South Wales, Yorkshire, wye valley are just a little further, about an hour more.
If you have the motivation or 3 days.... think bank holidays etc, North Wales, lakes, pembroke, deeper into Devon and Northeast. Are a similar distance time wise.
I guess just follow the good weather and decide if it's 3, 4 or 5 hours drive you're happy with. As long as you're ok accepting it's as drive to anywhere, it's not a bad location to find yourself in.
And if you are happy with 4 to 5 hours, the airport truly does open up Europe.
The selection of indoor walls nearby might also motivate getting outside too. They're ok, but it isn't quite as good as being outside......