Ok.
Developed this recipe based on some advice and a recipe from an experienced brewer on another forum (I think theirs was for the draught Young's special)
It's metric but I've included percentages.
Young’s special London ale clone attempt:
English Strong (Extra Special) Bitter
Type: All grain
Size: 22 liters
Color: 16 HCU (~10 SRM)
Bitterness: 36 IBU
OG: 1.060
FG: 1.012
Alcohol: 6.2% v/v (4.9% w/w)
Grain: 5.5kg Simpson's Marris Otter (91.7%)
500g Joe White crystal 50-60L (8.3 %)
Mash: 70% efficiency, 66 degrees, 90 minutes
Boil: 90 minutes SG 1.044 30 liters
Hops: 25g Fuggles (4.75% AA, 90 min.) (15.5 IBU)
25g Kent Goldings (5% AA, 90 min.) (16.3 IBU)
20g Kent Goldings (5% AA, 10 min.) (4.4 IBU)
Dry Hop: 10g target in secondary for 7 days
10g East Kent Goldings 7 days
3 L starter WY 1318 (London Ale III)
Mash 66-67
Caramelise 2 L wort (reduce to 300 mL) and add back to boil.