like you've said pretty good for it's time,the BBC shows usually hold up quite well with time IMO
Prof may well release it,as far as i know he's released the Quatermass and triffids shows so far from his poll....his latest release was
timeslip another classic show (not BBC though)...so far he's done 1 of the 4 series so might be a while till he may do Nightmare Man....maybe PM him at FH and let him know you are after it