You're more than welcome Bill, and yes, I forgot to mention the other jettison areas, one being the Wash, as you correctly stated, and I believe another in the northern part of the North Sea, used for aircraft returning from attacks on Scandinavia, or returning from German targets to bases in north Yorkshire and Co. Durham. I think part of the latter is now used as a bombing range and / or Military Aircraft Exercise and Live Fire Zone, or used to be - I remember NATO aircraft in he area up to at least the early 1980's. There are still 'live fire' ranges over the Wash too.