Just had a browse of CAP 774 Chapter 3 (Traffic Service) and I can't seem to find anywhere stating that I should have 'visual references' to avoid traffic. I am happy to have it pointed out to me as I would prefer to have the facts. It does seem bizarre to be IMC but have 'visual references'...?
I am loathed to use a deconfliction service unless I am really maxed out and don't have somewhere to be. If there is any traffic around it really messes up one's routing!
Also as Genghis said, if it's VMC then I see no need for a radar service!
