No reason the Avanti brand couldn't stay with the franchise is there? (It wont, of course, but it could, unlike say 'Virgin', 'Arriva' or 'First'.)
The rules changed so that incoming TOC's had to either sell their brand to the DfT at the end of the franchise, or return all the stock / stations to unbranded/ generic branding at the end of their franchise. Some have gone down the route of implementing a generic brand, but they're not required too (despite what some enthusiasts seem to think).
There was a lot of froth about how this was definitely going to become LMS with a maroon and gold livery, although I have no idea what precedent they were using to predict that, since only GWR has gone down the classic name and livery route.
At least this looks a lot nicer than the no-expense-spent purple we have over on EMR.