Flybe won't be feeding anyone at LGW using the Q400 unless the charging structure changes back. It was the move to favour A320 size at the expense of turboprops that caused flybe to close LGW in the first place, abandoning long built up routes to INV/BHD etc. Only NQY survived on the back of a taxpayer bung, LGW will not work for flybe unless LGW give them a very good deal, which of course they might, depends on how desperate things are.
Besides I don't see Virgin back at LGW for a few years at least.
Unless Virgin have the money to subsidise flybe2 to make losses at LGW for the sake of slot sitting for five based aircraft for a few years.