Gone back out to tender.Although the in house option is favourite with Serco as partners.A bit like the Fire Service partnership a few years back.
Where is your information from?
The tendering process has been completed, so I can't imagine that it has gone out to tender again unless BHX management have moved the goalposts and changed their idea of what they want.
NATS have a year left (should they not win the contract) which means any additional tendering process would result in a significant delay (it's a slow process) and, I'm sure someone with more knowledge about these things will correct me, NATS being able to walk away at the end of their tenure, thereby leaving BHX up a creek.