I'm an idiot. I've been working on building up a Surly LHT frame and was all going fine until I got to fitting the crown race.
I couldn't get it to fit properly and instead of making a cup of tea and watching some how-to videos like I normally would, I fitted a metal pipe on the crown and a bit of PVC pipe above that and rested the forks on some carpet and smacked the pipe really hard with a metal bar. When I stopped I'd gone through the carpet and put a small (1mm) dent in the bottom of one of the dropouts (not deformed them). After that I went to my LBS and they milled the fork down a bit and fitted the race.
I've inspected the fork really carefully - no visible damage or bending. Is there any chance hitting it that hard could have damaged it somehow? I just don't know enough about steel as a material.