OK what are you all talking about??? None of you are correct...!
Virgin Atlantic has alot more than 4 bases: MAN, HKG, PVG, LOS, SYD, DEL BOM and LON which is LHR/LGW dual base.
LHR-DXB-LHR is operated by LON and DEL crew.
DEL crew are work DEL-LHR-DXB-LDR-DEL.
They are used on the DXB route due to the large number of Indian pax on the flights.
Virgin Atlantic DOES NOT, HAS NEVER and probably WILL NOT, have a base in DXB.
In early april, V-Australia based in SYD, a subsidiary of Virgin Blue, which is a Domestic Airline in Australia, recently had a recruitment drive in DXB. This is a new airline, which will be operating B777-300ER, and the new airline needs crew who are experienced on this type. EK operates this a/c and there are lots of aussies working for them. No further recruitment in DXB is planned.
This may be what got you confused.
If English is not your first language, please be aware, that by using the term "I know for a fact", indicates that you would know for certain, which you obviously didn't.