This is one of the best threads and I thank all the contributors. In my 42 plus years in aviation only went to LTN a handful of times but do recall Court Line and Britannia. I flew on a BIA Herald to GCI one January after a snowfall and was able to observe the clearance of same from above the wings and fuselage.
A chap climbed on top of the a/c with a large broom and swept it clear, wonderful days!