My admittedly pure guess (since I haven't done extract brewing since the early 90's):
For ~21-22 L in the fermenter:
20 L RO water to start, heat to 160 F.
1.5 Lbs. Briess 120L Caramel/Crystal (or equivalent, steep in a bag @160 degrees F. for 30 minutes in 20L water)
Heat water additionally to 180-190 degrees F. post removal of steep bag, and then slowly add the DME's listed below and mix well
3 Lbs. Briess Goldpils Vienna DME (or equivalent)
6 Lbs. Briess Traditional Dark DME (or equivalent)
5 Lbs. Briess Sparkling Amber DME (or equivalent)
Make up at this juncture to 28 L volume with additional RO water, then heat to boiling
6 Oz. Fuggles, 60 min boil
3 Oz.. Fuggles, 20 min boil
1 Lb. Tate & Lyle's Black Treacle (add at end of boil, during cooling)
Rehydrate and then pitch 1 pack each of Windsor and S-04 yeast. Ferment at 64-65 deg. F.