Do those upgrades require availability of upgrade inventory or just an empty seat in CE (effectively that BA be willing to sell a CE ticket on the plane, given the moveable curtain)? And are they good (for the same number of Avios) from deep discount coach fares, including HBO? And are these upgrades confirmed in advance (as would happen if one simply purchased a CE ticket) or only on the day of departure?

ADDED: BA saves money by packing the same number of passengers onto fewer operating flights and not paying compensation or refunds. Even if the same number of staff must be paid (are extra FAs required when the middle seat is filled? I thought that was the purpose of the tables, to make the middle seat uninhabitable so that the required FA count doesn't include the middle seats in CE.), BA save on fuel costs when then can operate fewer flights (and fewer takeoffs and landings) even with the same total weight being carried.

As for staff, when one accepts an outdoor job at LHR our any other airport (or more generally with any employer), part of the deal is working in any weather when it's safe to do so even if it's uncomfortable at times. Ramp workers would get more breaks and be expected to be somewhat less productive in bad weather, but the bottom line is that they need to do their jobs (or find other employment).