I've adjusted by recipe for Randy Sparrow (scaled up to 50L batch and dropped the BHE to 70% from 75%) to account for efficiency loss to the extra hops.
There is one thing that I cant get my around....sparging, I normaly use 25L sparge water will I need to use more to get all the sugars from such a big batch

I plan to mash then collect 25L - 30L, boil with double the amount of hops that I would normally to end up with 25L wort that is around 1.090 (80 IBU) then split between 2x 25L FV's and dilute down to 1045 (40 IBU).
50L Batch
70% Eff
9250gm Pale Malt, Maris Otter (3.0 SRM) Grain 89.81 %
525gm Caramel/Crystal Malt - 60L (60.0 SRM) Grain 5.10 %
525gm Wheat, Torrified (1.7 SRM) Grain 5.10 %
120gm Challenger [6.80 %] (90 min) Hops 40.4 IBU
60gm Fuggles [4.00 %] (15 min) (Aroma Hop-Steep)
60gm Fuggles [4.00 %] (0 min) (Aroma Hop-Steep)