Try to cross you bridges when you come to them.
I worried and worried that I wouldn’t get my critical illness - not for the same reasons as you, but because I’d been to the doctor about a number of things over the years, which although not obviously neurological, I now realise were MS-related.
So I felt sure the insurers would say either I, or my doctor, knew, or should have known, I was already ill, before I purchased he insurance.
So I was really expecting a rejection letter, saying: “No, you already had it when you applied - look at all this stuff you’d been to the doctor about!” But in fact, they were fine. Although it’s easy to say with hindsight that my aches and pains were probably related, they didn’t think anything was such a red flag that a normal person (or doctor) should have seen what was coming. Nothing was challenged at all.
In fact, although I gave them the address of my consultant, I am sure they never contacted him, because I’d ticked the box saying I wanted to see a copy of his reply - which I never did. So I assume there wasn’t one, because they hadn’t asked.
Apparently, they were able to settle my claim purely from the GP’s notes, presumably because there was a nice clear letter in there, from the consultant, diagnosing me with MS. They can’t have thought there was anything suspicious or ambiguous about it, that they needed to clarify with him, so that was it.
I was glad of the money, of course, although I’d been half hoping they’d say: “We don’t believe you’re critically ill!”, as that would have given me a glimmer of hope I might not be.
I was shocked by how readily they accepted I had MS, and realised that if the insurance company wasn’t going to challenge, there was no chance of a last-minute reprieve. They really must be pretty damn sure.