Having read a number of threads on here, i understand that the risk of a downgrade from J to W (or Y) is considered low. However...
I have a 241 booking later this year - start of W21 season. Caribbean route out of LGW. As we were only able to get J seats outbound, there is a bit of cash left from the lower surcharges on our economy return. This is a rare treat for us to get away without the kids, so we're not anticipating on doing this for another 10 years!

Seats 1J and K have recently become available, but my wife is reluctant to pay to reserve seats, but I'm sure she wont be happy if we aren't seated together!

I appreciate only I can make the decision as to whether to book them, but please see my line of thinking below.

Pros:
We know we'd have seats together, albeit we were thinking a centre pair may be preferable.
We'd get served early with our first choice of mains.
We'd reduce risk of disappointment of being downgraded???

Cons:
£220 is a lot of money to reserve seats and I could treat Mrs Fo6 to some nice holiday clothes instead.
4 E(bassinet? blocked), F and G are still available, as are 4B and D (across the aisle not so great) - so we could still be seated together.
Summer flights have been re-routed, so a chance this could carry forwards into winter, which could mean seat changes anyway, I gather there are no refunds available.

So- can anybody confirm if having paid for seats (or selected special meals as one of us might) has any bearing on likelihood of downgrade.
Is the J cabin oversold less frequently on leisure routes than business?