According to the BA website flight status page RAK-LGW is in the air now and due to land at LGW at 17:51.
The 17:50 LHR-MAN flight has been cancelled, but the 20:35* and 21:40 are still scheduled. Hopefully you are already on or can be squeezed onto one of those.
* 20:35 now showing as leaving at 20:56