I had the same issue with my mum's first GP...then she changed to a gp that I think was about to retire so he saw sense and chatted to me. I made telephone appointments to talk to him. My mum passed the doctor's dementia test, but I persuaded with him to refer her to the memory centre. They should run full bloods to rule out anything else...urine infection, thyroid, deficiencies etc..
The memory centre got the referral and closed it down when they saw how my mum did on the test and also had no previous history with them.
I rang the memory centre and told them mum lived alone (they were open to talking to me about my mum), had crashed her car, was losing keys, purses etc etc they reopened the referral. I told them she'd lose the letter with the appointment date on for the memory clinic, so could they text me the date of the CT and memory tests which they did.
They did a ct and she didn't do so well on their tests. I went with her for the CT as she lost and forgot the appointment.
My mum would never have agreed she had issues, so I had to let the referral run its course.
I also shared my concerns with neighbours who talked about how they were worried about their memories so had done the memory tests to reassure themselves.
You could also have a telephone appt with the doctor and request a private referral for an MRI...they cost around £600 and you can get one in days.
Sending you hugs, the process doesn't work. Stay strong and perserve x