Precisely! It took a fair few whaks to get the steel to move the couple of mm's I needed, but I can get 54c tires in there now. Any bigger and you start hitting the underside of the fork crown...and there isn't too much you can do about that with just a hammer and some old scaff.I don't think the subtle approach would have been enough. I suspect the issue was tyre clearance at the BB end of the stays and near the fork crown, not at the dropouts. Jamming a bit of scaffold tube in the gap and whacking it in as far as possible with a big hammer would have flattened the tubes a bit more where their diameter is large. It's just a more brutal way than how a frame builder will shape the stays to achieve tyre/chainring clearance.