Yes.
However, availability, which has often been an issue, has been opened up so (apparently) many more of us can upgrade, or Not.
If you don't need to fly via LHR then it may be a better use of Avios to fly to Madrid and transfer miles to IBERIA (also have to earn a few and there is a short waiting time before activation) where the carrier charges are much, much lower.
Agree it leaves a bad taste but ultimately BA can do what they like...