Large hammers are wonderful and sometimes needed. Once upon a time I was changing the engine in a Marina and wanted to get the spigot bearing out of the flywheel. Having failed to get it out with a screwdriver the next step was to pack the hole with grease, find a drift the right size and belt it, which usually works. Not this time. Many hard hits later it was still there. In frustration I picked up a 2lb lump hammer, hit the drift and out the bearing popped just like it should have. Big hammers teach manners lol
I went to the 2nd engineering place yesterday and they only use 25x25x3 so no joy there, But they use lots of 1,3,5 and 10 plate and will let me rumage and they'll even cut to size and apply bends for me
Steve