What would be great is if somebody from BT Mail could publicly state whether this is a temporary glitch in the servers (and will be resolved) or a permanent new fixture relating to the migration away from Yahoo... in which case, those of us who rely on the Push feature can begin looking for a new service that does offer this feature.
As I said before, it's probably temporary in true BT Yahoo! fashion. If you really do need the Push feature though, you may as well start looking now because you certainly won't have it when you're migrated to BT Mail unless things change.
My husband's seems to be working intermittently now, but mine is still not showing any signs of pushing!