Someone in the FB group I'm in went to their Biometric yesterday and were given a new letter that did reflect this new address. So I guess that is something.
That's good - when they initially changed the settlement visa processing from New York to Sheffield in 2013, it took months for them to update the address and it caused all kinds of confusion!
At first, New York would forward applications to Sheffield, but after a few weeks, they started sending applications back and telling people to mail them to Sheffield instead... so if you did send it to New York by accident, it could add up to a month onto your processing time, while you waited for them to get to it, then mail it back, not to mention the time it took for Sheffield to receive and acknowledge it!