Changing planes

A couple of months back I booked two UC flights using miles plus money to St Lucia on VS031 and reserved seats. A few weeks later I got an email cancelling the flight and rebooking me on 037 leaving at the same time with a stop in Barbados. When I checked my seats we had been split up to either end of the small UC cabin - which was reasonably well resolved following a call to Virgin.

Now on checking my seats I see that we are on a LHR config 747 and there is plenty of seat choice. What's going on here?

Barbados is a popular route for UC bookings, so VS sometimes use an LHR config based on demand, as it has a lot more UC seating.

Welcome to V-Flyer, as said above BGI does have high UC demand so it's not surprising to see this happen - but it does show that it pays to keep checking MMB to spot such events.