UK - privately diagnosed, seeking medication through NHS

Hello,

My situation is pretty much as the title says. I have contacted my GP who has said that they have sent off a referral but the waiting list for a psychiatrist appointment is 1 year plus. She seemed to suggest that I may need to have another assessment.

I looked into getting diagnosed privately as I had hoped this would avoid the wait for medication through the NHS.

Has anybody had similar experiences, and did you need to go through a second assessment?

I do feel like it seems a waste of time and not to mention NHS resources to ask me to go through another assessment to diagnose an issue which has already been diagnosed.