Hi Both,
I was recently worried about this as I take blood pressure medication as a young hypertensive. With Medication my reading on the day was 148/86 and this was passed fine, I think he mentioned if it was 150/90 or higher for either Systolic or Diastolic it would be flagged for review with BP home readings to be provided, but I passed all fine and now start in 2 weeks time.
Generally seems to be fairly receptive to readings and understanding if you take medication, but I would imagine for a home reading they would want around/below the 150/90 mark resting, deep breaths and sitting still for a time all help lower BP ahead of a home reading.
Best of luck to you both!