You really will have to explain to me what version of democracy you would like to see in place to meet with your approval?
The system we used saw 52% of those who voted choosing to Leave- that is a majority by any known mathematical criteria?
The turnout was extremely high by modern standards 72.2% and significantly higher than that seen for the last general election- so no problems there then ? If the referendum isn't valid then neither is the Parliament
The terms for the referendum were set by Parliament where remain MP's were in a majority - they were happy with the demographics of the referendum and passed the necessary legislation by 6 to 1, effectively handing the matter over to that part of the population of the UK deemed eligible and responsible enough to vote by Parliament themselves- so all hunky dory there too surely?
If you are going to try and belittle the wishes of the 52% majority by describing them as only 28% of the population, then you are inferring everyone under 18(including new born babies) should have a vote as well as all foreign nationals living in the UK? I suppose in the ultimate democracy that might be fine (although we might end up with Adele as pm) We could even give pregnant women and soon to be fathers an additional vote too ?
All that last paragraph is of course utter nonsense- the terms of the referendum were clearly proposed, discussed, set and approved in a eminently sensible and transparent manner and the result should be respected. To say otherwise is undemocratic in the extreme
The only "democratic" elections where one party gets 99% of the vote on 100% turnout (which appears to be the only result you would consider valid) are those organised by Robert Mugabe et al
and of course by your own logic only 24% voted to stay in 
