I would think, if you have been prescribed medication, that your BP should be within range fairly quickly, but that will depend on how high it was. Your doc also may be concerned about the effect on your heart, as prolonged untreated hypertension can cause enlargment of the left ventrical. This would be picked up on an ECG apparently.
As others have said, betablockers are a bit of a no-no, and you wouldn't get through an HSE diving medical on them.
I don't have any problems with Lisinopril, but then I also didn't have any problems with the beta blocker I was on before it.
Best of luck and welcome to the club
!