On Sunday, 10 March 2019 22:26:10 UTC, Dave W wrote:

It's the grey look I'm after ideally!

I don't think you can buy panels that have been weathered as much as
yours. I suggest buying new panels coated in something you can paint
on the weathered ones to look similar.

As I said it really is the natural grey look I'm after, and am not keen on applying anything that I may have to redo.

I think I could live with the temporary greenish tinge of tanalith and I'm sure I'd cope with leaving it to weather naturally after that. It really was the heavy orange colour that I kept seeing on most of the panels I came across.