I continued to search out old cold room panels. One thing that came to is the cost. Although I would be ultra efficient and thermally insulated, it would have to be cut and fettled into place, so if I needed to move it, I may have had to purchase more bits, deassemble reassemble.
So I am still keeping that as an option. I will have to list the pros and cons so it gives people reading through my barble something whoch tailors their needs and situation.
Shipping containers! This has been another option. But expensive and would need special expensive delivery for tight access. Blah blah
Then I stumbled across flat pack containers. Banging. They look good, accessible and yet less expensive.
Then for half the price or more again, I found a steel corregated shed, which suits perfectly.
All will revealed and I will post more later. I have stopped my grows now and concentrate on my groom. For security reasons after moving house
For now though, Happy Growing Every One Of You.