I did a quick analysis for you.
The cheapest biz basefare in the market is $1097. After taxes and fuel surcharge that probably comes to $1800ish, not too far off from £1200.

It looks like BA is simply restricting inventory a bit because they think they can sell for more. Whether this is temporary I do not know; maybe you need to look further out when booking.

But the bottom line is the base fares are still there.
Sorry I can't help more!