I paid privately to see a cardiologist when I kept being given telephone appointments, or seeing a locum at my surgery, and no one would help me when I was having terrifying heart problems and had had 3 bad "episodes" lasting all night.
A&E in my area is even more dreadful than nationwide so I was reluctant to call an ambulance which (a) wouldn't turn up, or (b) might take many hours to arrive (both experienced by local friends.) or (c) would leave me sitting in A&E for 12+ hours when I have multiple health issues to take account of, one of which is fairly severe M.E.
I asked for an echocardiogram and a doctor told me no, giving me the impression I didn't need it and making me feel I was making a fuss, but I saw on my records on the NHS App that she had put "No referral for echo due to service being overwhelmed".
When I saw the private cardiologist, I got an appointment within a week for an echocardiogram, and within another week to see the cardio, and she was horrified and said I could have had a stroke by Christmas. She prescribed a beta blocker and an anticoagulant and reported back to "my doctor" so I got these meds on the NHS, but I had to push for them as her report just languished in someone's in-tray.
I use the term "my doctor" loosely as I have no idea if he is still at the practice, having only seen him once since the start of the pandemic in 2020.
We have to advocate for ourselves these days so I would advise anyone to pay for private tests if they are getting nowhere with the NHS. I used my credit card because I have a low income and it was not as expensive as I feared. A friend's husband in Wales died because of NHS delays in fitting a stent. I didn't want to join him.