Blood sugar diet would be ok, limit oils and meats to reduce cholesterol. Exercise is going to be key for reducing blood pressure, start with brisk walking twice a day for 20 minutes & build up to 30 minutes 2x per day. Then either add in running (coach25km) or cycling. The diet on its own won’t reduce the BP you need to exercise
blood sugar diet/fast 800 is perfect for weightloss and health. but have a look if it would be sustainable for you. sadly some people need medication to control blood pressure, but losing some weight will be beneficial for your health nonetheless.
Losing weight of itself will probably help. The advice for reducing blood pressure fits in well with most healthy eating diet plans - reduce salt, saturated fat, added sugar and alcohol, increase fruit and vegetables. Michael Moseley's blood sugar diet is low calorie and mediterranean food so would fit all those criteria. The important thing is finding something you can stick to in the long term. Good luck!