Towed van/car combination today to get weighed today and it towed very well, about 100klm round trip @18l/100. Perhaps little stiffer springs in the rear would be nice dropped 50-70mm with 266kg tow ball download. (I'm used to 400kg rear springs in 100 series - fantastic for towing but bad without van on corrugations) Here's some weights for those interested - Trialmaster with bar and winch, two adults with empty 35litre fridge, considerable tools. No drawers or awning but these are to be fitted.
GVM as above 3220kg no van (330 kg's available)
GVM with van attached 3498kg (52kg's available - close to 3550)
GCM 6320kg ( 680kg's available)
Front axle no van 1612kg (55kg's available - close to 1667)
Rear axle no van 1608kg (542kg's available - not close @ 2150kg's )
Front axle with van 1524kg (143kg's available)
Rear axle with van 1974kg (176kg's available)
Not bad but front axle as suspected is close to max when no van is attached yet I still have considerable payload left. Front axle is all good when van is attached but then GVM is close to max. Still perplexed as to why front axle load is so low as is not dissimilar to Y62 or 300 whilst rear is very good. Overall happy as, towed well, economy good. Likely look for small GVM upgrade so I can travel with awning/crossbars and drawers and hopefully this will also come with a little stiffer rear springs.
Oh, one other thing. I have my van dc to dc charging from the nato plug. When I turn the ignition on, 500amp consul switch on and then into drive I hear the rear solenoid clunk on. It stays connected for a few seconds then drops out with a plug/canbus error coming up. Have no idea why. I then connected the 'compressor' relay signal wire to the nato solenoid (this wire replaces the solenoid +12v signal wire) so I now have permanent power to the nato plug with vehicle running and it ran the dc to dc of the van with no problem whatsoever. Not sure why the standard set up didn't like my dc to dc via the nato.