The risk to women's health from having hormone therapy arbitrarily and unilaterally withdrawn far exceeds that of continuing it and treating the blood pressure if needed.
It is extremely likely that your blood pressure is lower not because of cutting down your HRT but because you are checking it at home, not stressed at the GP surgery, particularly if you are in the situation where access to much needed treatment is contingent on obtaining a particular number. That in itself pushes it up.
I would be very firm in advocating for yourself and not agreeing to have your treatment withdrawn.
I would consider putting in writing to your GP at the same time as handing in your BP diary exactly what benefits the HRT brings to you, for example being able to sleep and exercise, as well as your quality of life, and list any risk factors you have for osteoporosis, and include a link to the relevant section of the NICE guidelines recommending against arbitrary time or age limits being placed on treatment duration.
As a last resort you do have another card to play in terms of agreeing to transdermal, but I personally wouldn't give up oral without a fight as patches/gel are unreliable and don't stick well.