We looked very closely at installing rear-facing seats in F27-400s in the '70s, because the safety case was so strong. But we were defeated by the need to lose 2 seats as a result of the extra weight. The accountants were appalled by the notion that 2 seats, out of 44, should be sacrificed to safety. Only the RAF got away with it in those days, and very comfortable those VC10s and Britannias were as a result. My memory fails me on whether trooping contractors such as Eagle also had them.
The weight issue came from the need for the seatback and reclining hinge not to collapse with up to 9G load with an occupant of up to 18-stone/115 Kg (I think it was...). Some of the weight could be removed if the seat were non-reclining, but not all by any means.