Bealzebub's advice is spot on. I have high blood pressure and am on an ACE inhibitor not the Beta blocker as mentioned on the beeb today. It was found on my Class 1 renewal but there was no drama. They simply asked for a 24 hour monitor which proved it was high even in bed asleep. I was put on medication successfully. The irritating thing about high blood pressure is that you feel exactly the with or without medication. The only difference is that you will probably die of some related complication if you fail to take your medication.
A Doctor told me that high blood pressure is a game of halves. Half the people who have it don't know, half who know don't take medication and half of those who take medication have side effects.
The biggest problem I found with hypertension was that when I applied for a mortgage the racked up the insurance costs even though I am on medication. Rather ironic, on meds the risk is considerably reduced.