Thanks guys
Already started removing most of the cans of food, toiletries, etc, as i heard the cans can rust sometimes. I knew about the water drain points, and draining the gas boiler coils, and i also can 'borrow' some glycol from work to put down the u-bend of the loo! Never really thought about spraying the vents with flykiller, good tip!!
Already have the packs of crystals, and i can 'borrow' (again!) some dessicant packets from work too for around the smaller nooks and crannies. I have a small portable dehumidifier, but if needed, i can take down the larger one i have at home. My parents have those vacuum packs too, but i think i will just bring my bedding home as i have enough space to store it in.
I think my mum is planning to take the curtains down and leave the mesh curtains up on their own, but they have plenty of storage room at home, so i aint arguing!

Also, a great tip to check the bottom vents, will make sure i do that before leaving
The best thing, is that the static is only 20 mins from where my wife's family stays, so when we go visiting at weekends, we can easily pop down to check the van