Just don't try using RUH (Riyadh) as a starting point for a RTW without entering the country for a night with the appropriate visa. We recently finished an AONE3 there and had return boarding passes issued at LHR for the RUH-LHR 1st segment. Upon arrival we were detained by Immigration, then by some scary army guys with rifles. They simply could not grasp why we were arriving on a BA flight and turning right round and returning. After two hours of worrying opposition we were allowed into the departure lounge and made the flight with minutes to spare. The absence of a visa seemed to be the major problem. It should also be mentioned that the treatment of my wife was disgraceful; she rightly refuses to finish this existing RTW in RUH so I've changed it to CAI which has once again become one of the better places to start a further RTW.