Had been looking at potential 500 nm trips. Don't really want to sail across to Norway or Denmark as will have to get back again doubling the time away. Was thinking about sailing North East (ish) round Holy Island and back but as you suggest there are the oil / gas platforms to consider.

Centaur Pipedream has recently got back from the Azores and did the return trip solo all the way up channel so I am interested to have a chat with him and see how the last bit was - potentially at his most tired with the busier shipping lanes too.

Good luck with the preparations.