Shot a good few roe with .222 in Scotland, it's an excellent round for them. .223 is just as good if not better I'm sure. Chest and neck shots, nothing ever ran far. Using my 25 06 on roe in England always seems like using a sledgehammer to crack a walnut by comparison.
It's good enough to shoot people with and that's without expanding bullets, so theoretically it should be fine for Roe!
There are some strange differences between Scottish and English deer law which would be better unified.