Hi Michael
I assume you knew your PSA level before you started Finasteride? Are you aware that when Finasteride is used for treating an enlarged prostate, the dose, (usually 5mg/daily), will half your PSA readings over about 6 months. (example: if your PSA was 6 before starting Finasteride, it should halve it to approximately 3.)
In order to get an accurate PSA, you would need to have not been taking it for several months and maybe longer. If you had your PSA just after coming off Finasteride, you should double the figure which would give you a more realistic PSA score.
Keep the pressure up on your GP for a referral to a urologist, so they can address your enlarged prostate in more detail.
Best wishes,
Seb