It's not just about dying a few weeks early, heart attacks and strokes can cause years of disability. From the link you gave, even that doctor would agree that treating a BP of 150/98 would be worthwhile. However, he is just one doctor whereas Nice guidelines are developed from a consensus and are based on the best available evidence
https://www.nice.org.uk/guidance/cg127/chapter/1-Guidance
If you want to try lifestyle changes, there is some advice here:-
http://www.mayoclinic.org/diseases-...ure/in-depth/high-blood-pressure/art-20046974 As you say, weight loss may help.
The problem is, I don't believe, at all, that NICE guidelines are based on a consensus and the best possible evidence, because I absolutely believe that much medical research is fatally flawed and unduly influenced by commercial interests. A quick look at the Mayo guidelines reveals, to my mind, some good advice, but some bad, that has gotten us where we are today. Yes, we can all agree, stop smoking, exercise more, avoid stress, but I would absolutely disagree with the dietary guidelines - a low fat diet? Eating whole grains and fruit? I don't think so! The thing that lowered my blood pressure spectacularly was a high fat diet, no grains, no fruit, aka Atkins, LCHF.
So from years of being on Atenolol (which gave me awful swollen ankles and restricted my mobility - counter protective in terms of heart health) and Ramipril, I am now drug free. Hibiscus tea, I think, helps, as does ground flax seeds.
And following a LCHF diet you NEED salt, just make sure it's good quality, natural unrefined sea salt. Again, all of the research on the harmful effects of salt were conducted using normal refined table salt, I don't have that in the house. My salt is bought from the producers, on the salt pans of the Ile de Re, and lovely stuff it is.