That is exactly what London did to me a couple weeks ago, and when I told them I was an Appropiatley rated pilot, the radio went very silent, and then a reply to the extent of OH we made a mistake. I am still upset over that. I file what the MEA is on the chart or higher and in this case I am either at MEA or 2,000 above it.
I do understand what you are saying, and maybe the UK system is simpler? and maybe it isn't. but when I file a plan at 070 in my mind I am clearly indicating that I am not just an IMC rated pilot, especially with the airspace around he London area. Yes I understand the no single engine over the city of London. but to plain disregard a filed and approved flightplan is just wrong, and makes a person wonder. Oh, and I get questioned on one flight From London again, "Are you sure you want to fly this plan and that altitude" a direct quote, and had to look at the passanger I disbelief, and answered yes I do.. I think you know were Iam coming from when I ask what I do. I wil read your PM in aminute.