Sorry to butt into your post Edd and go off topic (try cleantech?)
I've been waiting to catch you. I have decided I want a hot system and would like your advice.
On one post you mention webasto heater for £1000, but I have been unable to find such a product.
I have seen a caravan shower system at £1,500
and on windowcleaningservices site diesel thing at £2,500
Ionics don't give prices or details.
I see on another post of yours pictures of modifications you have made to a thermopure. Is this your system?
I have 400l in a scudo and would like to turn it into a hot one, what are my options, or your opinion?
(My winding arm broke but i had it welded. I keep a spare reel.)