Or you could just try the Wheeler recipe, which is on the Worcester Hop Shop site as a grain kit:
Light DME 3kg
Crystal Malt 295g
Chocolate Malt 215g
Challenger Hops 30g for 60 mins (could just use Fuggles)
Fuggle Hops 14g for 60 mins
Fuggle Hops 14g for 10 mins (Wheeler says Goldings here but Theakstons say Fuggles)
S04 yeast or Wyeast 1469. Or WLP500 belgian ale yeast, which one online blogger used and reckoned it worked really well in his OP clone.
they sent me 25g challenger
14g east kent goldings
14g fuggles for that kit
and the grain was
5460g maris otter
295g crystal malt
215g chocolate malt