DXB Shuttle ?
Flight time from LHR to DXB is somewhere between 6:30hrs and 7:15 dependant on the time of year and the subsequent prevailing winds.Factor in a 90 min turnaround time and the duty is around 16hrs.
If it does not become a shuttle then slip time will be determined by flight frequency.If its daily frequency with a fight time EX LHR of say 7:00hrs the slip would be around 20hrs
If the bean counters consider one or the other do able the base will close itself down through an accelerated attrition rate.With the cessation of through traffic from Asia to the UK flights will reduce as will destinations for LHR based CC.
The numbers required for the base will also decline.The base as an operational entity then becomes marginal.
Good Luck.