Well the competition (LY) charges £981, so if BA can get away with charging the same (or £50 more), then you can't blame them surely. One-way fares have always been a rip off, and until you get LCCs forcing them introduce normal one-way fares, that isn't going to change.

Those that want to can go on OA for £184 via ATH or LH for £231 via FRA.

There again, if you want to go on BA, there's an easy way around the full one-way fares - buy a cheapo return fare for £321 in N class, and throw away the return.