Sorry @LadyG. I'm not trying to confuse you, just help
I've had a quick look.
The £400 is completely separate to the Winter Fuel payment for OAPs.
The Winter fuel payment thus year should include a bonus for the current situation. https://www.gov.uk/winter-fuel-payment/how-much-youll-get
Depending on your financial circumstances, and on how things work out for helping people who aren't connected to the mains for gas and electric, you might be able to access additional financial support.
When the new government has settled in and decided exactly what they plan to do, it might be worth contacting citizens advice to check you are getting everything you are entitled to. For boaters, who Citizens Advice probably aren't aware of much, keep checking on here what other people are able to claim.