I'll have a poke about in my scrap bin(s) tomorrow,
Thanks, that's solved it.Thats a standard ERW size 1.75" x 12swg, ebay will probably turn up a piece, I'll have a look on my rack on Monday, I have used it in the past but I dont know if there is any left, I tend to dump small pieces.
edit:
https://www.ebay.co.uk/itm/44-5mm-1...517462?hash=item4d35f1bf96:g:SjcAAOSw~gRVt6pB