Yesterday I asked a mate to ask the body shop he uses and he randomly had a 1/2 a sheet of new 3mm so he gave me that.
Another metal supplier I know sold me 1/2 a sheet of 0.9mm and had some 1.2mm scraps I could use for small brackets and another mate gave me a new patten wing the he bought to cut the arches out of.
So I now have plenty to work with.
I am cutting it up with a grinder with a 1mm disc.

The idea of cutting repair panels out of scrap/breakers would be lovely but it's a 25yr old Renault 5, so there's none to cut parts out of lol.

The reason I wanted 3mm is I'm using it for new strut tops so wanted to make sure it was heavy duty, especially as I'm cutting most of it away.