AEUlad,
Though I agree that the flights won't allow for much CAI-US traffic, it certainly offers a good alternative schedule to that offered by the incumbent carriers on the route, BA and MS, who depart LHR in the late afternoon and depart CAI in the early morning.
As for the turnaround time, I agree 50 minutes is certainly tight. Though it won't be an issue getting the aircraft ready in 50 minutes, it doesn't take into account any possible delays of the inbound flight (quite common on flights ex-LHR). Furthermore until CAI's T3 opens next year, the airport is certainly burdened with more flights/pax than it was designed for. Thankfully the airline will be operating from the modern and 'new' Terminal 1, as opposed to the 'out-dated' T2 which is used by most international carriers.
As for it being a 'killer shift', it all depends on how BD will manage these services. If their crew stay overnight in Cairo as opposed to operating both in/outbound services as most UK charter airlines do when flying UK-Egypt-UK services then it will be quite an easy shift...a short 5 hour flight (Egyptian pax aren't too demanding) followed by a 22 hour rest.