First off Grid trip

Loads of solar panels available on EBay. We were comfortable using a 100 watt suitcase panel but found it a bit lacking on really overcast days so added a 50 watt panel. Battery is class A 115amperes.

10 kg Safefill bottle takes care of our gas requirements at a much lower cost than rip off Calor.

If you move around a bit, change sites every 3 days or so, OR use a MH regularly to visit places, then it's relatively easy to stay powered for many days as the batteries get charged that way...

the acid test, a fortnight or more on a THS type site without moving the van at all. You'll definitely need a good solar system and a couple of good batteries to be able to sit 'indefinitely' like that...it gets even harder when you change Ebike batteries every other day....

you need a good size solar to keep your battery topped up, I recommend 160 watt

but if you are going in the winter you will also need a generator as the solar puts out next to nothing at the moment

go for 7.5 kg . safefill  we use about 5 k.g. in a week, the larger one will be tight to get in your locker

I wouldn't use ebay solar again, a lot of them are cheap ones from china

try Photonic universe, check if the club still gets you discount with them

+1 Photonic Universe, Sunstore Solar are good too.

All solar panels (and controllers) aren’t the same, they vary in type and efficiency, it’s worth doing some research before you buy.

Generators are a contentious area…. a lot of folks don’t like them and you may find you don’t have too many admirers when pitched in peaceful off-grid locations!

Why do you need a fridge for a week? Campers with tents live outdoors without one easily enough. Shop daily for perishables - or eat at a pub, but cooking on a gas hob for a week won’t exhaust a cylinder. Charge your phone in the car when you go out . Buy a portable Camping Gaz lantern. Live simply. Many of us caravanned for years before there was any grid for us to go off it. 

Nearly all solar comes from China.    So do controllers including those with fancy. Brand names.    A £6 controller won’t work as well as a £100 one but they still will come from the Far East.  

Good point. There are many products sold all over the world by respected brand name companies, with products or components made from materials of undisclosed origin. You can get a Certificate of Origin in Europe, for example, for products containing entirely components made worldwide. China has many infant companies, it's true, but also great technology and manufacturing know how. Remember that a few years ago we spoke disparagingly of "Gerry built" products, but look at Germany now. 

I think you'll find the average family unit in a tent will plug into the EHU and many take mini fridges and electric cool boxes with them. Some sites provide freezer facilities but if you're into very basic camping then I suppose you'll manage without although I think the OP wants a bit of comfort. 

If you need to charge your caravans battery that week your away connect your car back up to the caravan and leave it running for a couple of hours to recharge your caravan battery