said, get a Non O. You’ll need the insurance for the initial application but not for any subsequent Extension. Saves you buying a second policy each year when you already have insurance.
the RTE London website says 3 months so, as they handle applications, I’m going by that. You could always contact them to check everything as I’ve been told they don’t actually enforce the insurance requirement even though it’s on the website.
It’s been a requirement for a while but if it’s a Non O for being over 50 then it’s either proof of pension OR the 10k for 3 months not both. I recently got a Non O and used an occupational pension.