Things have moved on a lot since then, with the setting up on a new charitable trust to manage the waterways in place of BW gathering pace, but I've now had an email from "HM Government" (!) with their response.
After explaining the proposed change in status, the response continues . .
The Government will give the new charity the best start it can afford, with the transfer of the property portfolio and a long term contract. As a first step, the Government has provided a new long term commitment to a grant allocation at the 2014/15 level (£39m) to 2022/23 inclusive (covering the next two Spending Review periods) that will enable the development of a funding plan which gives confidence to the incoming Trustees of the new charity. The amount and length of the contract will be subject to negotiation with the Trustees, who will be appointed this April.
You can read the full response here