dorcas61,
Cutting back or eliminating caffeine will undoubtedly help reduce bp (albeit in a small way) as caffeine has been proven to increase bp in people, although there are coffee/tea addicts who maintain good bp so this cannot be accepted as the norm, but anyway its surely worth trying.
I stopped drinking caffeine drinks around 3-4 months back due to IBS (bladder in this instance) and have noticed a huge difference, from going to the loo every 60-90 minutes I now go around 3 hourly, and from waking 1-3 times a night, I can now sleep for 6-7 hours before needing to go. Without demonising caffeine, it is something worth giving up to aid health should you believe it may help, and as the decaff versions taste identical .......there is no reasons not to give it a try!
Nigel