Amazingly, on a day to comparison, after 2 days driving, as well as seeing 30+MPG regularly on the instantaneous display for long periods of cruising, not just flicking in and out on over-run.
Best bit, when the brake was binding, 1/4 tank showed before I got home on Monday (during the first two weeks) and 21mpg by the end of the week. But today, driving in my normal James May, Captain slow style, it is not yet down to 1/4 tank, which suggests I have used less than half what I was using. I'm not suggesting I'm going to get 40+, but I am stunned at how much the brake was binding considering there were no flames from the brakes.