i know this wasn't the question, but 650ltr a WAY to much for a dispatch
from information taken from
www.whatvan.co.uk a 2002 2.0 HDi 900 (the top model at the time) has a payload of 900Kgs.
650 ltrs of water = 650Kg
Tank = 40Kg
pump = 3Kg
Poles (average 3 of) = 20Kg
roof rack = 15Kg
di filter = 20Kg
1 set of ladders = 15Kg
Hose Reel = 20Kg
80ltrs of fuel = 80Kg
Driver = 80Kg (average person who likes a bit of bacon)
Passenger = 80KG
Grand Total of 1023Kg, and thats not including your trad equipment, extra ladders, wood lining, waterproofing etc.