LHR might see 1 x 333 daily to MCO, 1 to BGI and 1 to various islands on different days, maybe as double drops as a start.
As RLF says above, it could be that tentative restarts to carib routes may initially take a double drop route on previously direct routes as and when islands open up to travellers. With the cargo traffic on top for a pair of islands that could prove viable within a couple of months if islands can reopen for tourists.
For the islands it's obviously very difficult economically and planning for reopening may need to include many restrictions or procedures that could be impractical for their cruise ship markets but might be more practical for 1-2 week visitors....and it's quite possible that leisure customer appetite to 'take the plunge' will return quicker for air travel than for cruise travel too.
It's hard to envisage in the immediate future any carib island coping with 2 or 3 cruise ships of 2-4,000 passengers a ship calling in each day - probably only Cuba could cope, unless all their medical staff are now overseas that is. Could an island perhaps cope daily with a couple of 300-ish seater flights from UK and another couple from USA and/or Canada if the passengers were then on island for 1-2 weeks so justifying health checks on arrival (if the 'instant' test kits ever get working reliably) and provision of further local testing or screening if anyone falls ill?
Anyway, feel very sorry for all the VS and VH staff going to be affected by the job losses (I guess it's lucky Virgin Voyages haven't got too far underway), all the airport and off-airport support staff around LGW that will suffer job losses as their BA and VS business relocates and all the people on the islands relying on tourism too.
Meanwhile, I will be hoping Corsair don't go under (they are early retiring their last 747's too as part of rationalisation) as don't really fancy ORY-PTP back on Air France again...