College list it

depends on the length you need. I’ve had some similar sized gauge plate from here.

Have you tried your local steel stockholder? You will probably have to buy 3m but i will work out cheaper than buying a couple of feet from a ME type supplier and you will then have a lifetime’s supply.

Local stockholders don’t seem to keep much in the way of small imperial section and even the ME trade don’t seem to have that size so no doubt hard to source hence they charge accordingly.

Does not help that a lot of the ME trade deal in short lengths and often don’t give much of a reduction if you buy longer lengths.

Pitty 2.5mm flat is not readily available as 3 x 12 may be a bit thick for your needs but again length plays a part, someone like Ringwood charges £5.10! for a 330mm length but at least they reduce to a more reasonable £9.18 for 3m supplied as 3 x 1m due to carriage constraints. You do need to order a few things to spread the flat rate carriage out