just in case anyone wants to know. I have a 400 layflat, one pump, one reel, 2 poles, full tank of fuel, one driver who is about 6ft2 and 14 stone.
The tank was a little off the top in terms of being full and the total gross vehicle weight was bang on 1700kg the pay load is 595kg and the overall limit is 1700kg
So the moral of the story is 400 litres is to much. 350 is the limit and 300 should be comfortable.
If you have 2 men plus all the gear then i'd be lost