Was the 46 day cycle a one off? Was it after a covid vaccine? I've read of many women, me included, that have had a delayed period after their vaccine.
My understanding (could well be wrong) that a cycle length + or - 8% is considered normal, so (very roughly) if your normal is 32, then 29 or 35days is still within 'normal'. 46 seems way out though. I assume you checked you weren't pregnant that time?
Have you had any other changes since march, when your cycle changed? More body/facial hair, weight gain or loss, anaemia or a deficiency, thyroid problems, feeling the cold, hair loss?
In hindsight, I wished I'd pushed for a fertility specialist referral sooner. I do know that GP's have certain criteria they need to abide by in terms of testing, and maybe they really cannot do further tests on you, until your partner has a semen analysis. I don't know though, because ended up paying privately as got nowhere with my own GP.
For example, I was 1 week before turning 35, and had TTC 11.5mths, but was told that as I wasn't yet 35, nor TTC 12mths, I didn't qualify for ANY blood tests or checks to be done!!! Apparently the surgery don't get paid for doing such tests 'outside' the recommendations!
Do note that if you try to change GP's, it can be difficult to register elsewhere in many areas. In pre-covid times, the turnaround time to get files to the new GP was a min of 6 week. Now, I'd have no idea, but likely much longer. Best of luck though,, but do start with seeing a different GP at your surgery, and explaining the change in cycles and TTC for 3yrs.