We spent the winter of 69/70 in Malta with no electricity. I would not like to do that in the UK though, as you would probably ruin your motor from running it off load a lot.
For heat and light we used a tilley lamp, I fitted whale footpumps for water and bought a secondhand kerosene fridge for £5 which made wonderful ice in summer too.
We too used a solar shower and filled our calor cylinders from local ones using a piece of plastic tube. The soak bucket worked well for us also, a family with 2 small children.
The next spring we set off on a leisurely cruise ending in Falmouth. We visited 75 harbours on the way and didn't have to pay in any of them. In those days even in marinas you normally had a free night. I wish it were the same now.
I would happily do the same again, the whole point was to go for a simple life. Money does not buy happiness.
-------------------- James
Dolphin of Menai
Beneteau Oceanis 311.