On further investigation, the figures from Rave show for a 4.6 auto:
kerb weight 2220kg
Front axle weight 1165kg
Rear axle weight 1055kg
Yet the normal tyre pressures are 10psi less in the front......
However, add 3 fat bastards in the back at 100kg each plus 300kg of luggage plus 100kg of trailer noseweight and you then have (with two fb's in the front:
Front axle weight 1365kg
Rear axle weight 1755kg
Then the 28/38 pressures start to look a little more sensible.
As 90% of the time there's only me and t'other half in the car, I think I feel a twiddling session coming on when I get home......