I would try for 2-3 months with ovulation strips, bbt measurement and conceive + lub (+ ensuring you both take vitamins, eat healthily).
Hi, start with the basics which the GP would do such as iron studies, test for coeliac disease, thyroid studies, folate, vitamin D and vitamin B12. These don't cost the NHS much as so most GPs would approve to get them done. Make sure you get them done for both partners as it's important to correct any potential nutritional deficiencies for both partners in order to optimise both sperm and egg health
My husband went for a semen analysis as soon as I came off contraception, this was planned because he had mumps as a teenager and has a known varicocele in his testicles so we knew fertility might be impacted. Low and behold he had almost no normal sperm at all and we were recommended to go for ICSI. I would say if you can and want to, then have a full fertility screening at an IVF clinic, we paid £225 for both of us, bloods and scans and semen analysis included
I was given the advice to lie to the GP and said we’ve been trying for more than a year. Obviously we didn’t follow and so wished we did - could have saved us 2 years of investigations… but seriously, 2 things I’d say: 1) read the book ‘it starts with the egg’ 2) find a clinic to track ovulation with ultrasound & check your AMH/antra follicle count just to know how much time is on your side.