Thanks Gafferbill. This blows the radial tyres not getting flat spots out the water then? The only thing i would question is, this probably relates to car tyres and maybe not tyres designed for higher loads such as trailer tyres?
I think my plan of action will be using the relatively cheap wheel blocks that have been posted on this thread, checking the tyres pressures regularly (I will probably inflate the tyres to the maximum pressure stated on the tyre, rather than the recommended pressure in the caravan handbook if that is higher), and do quarter of a wheel turn with my mover monthly.