Our backgrounds and interests are little similar in that I did electronics in the U.S. Navy for 26 years and then taught it in University for another 10 years.
My approach to shooting is similar to yours as well since I like the scientific aspects. Although my interest does not manifest itself in better accuracy since I am a lousy shot.
I did not read the article you have cited but I think there is no reason to believe it is any less reliable than anyting else out there.
That includes what you said about the "spread" of the shots in terms of MV which seems to agree with what I have experienced. 65% of shots form the first SD (well duh!) and the rest are a little out there including the outliers.
I think that several of the members of the forum have used chronographs more extensively than I have. In previous discussions I can recall some complaints about the accuracy and reliability of the data they provide. Others question the rationale of using them in the first place stating that MV is not important to them since they shoot CAS which uses very light loads to the detriment of MV.
I went through three of them before I found one which would give me descent results. That is the CED M2 at about two hundred bucks. Some would say that is not a lot of money for a highly precise electro-optical instruments but the process of making the measurement is (as you might imagine) quite simple and not requiring much in the way of expensive components. We did it in one of my digital principles classes for about twenty dollars worth of parts.
I am not familiar with the rules on handgun ownership in the UK or the ease of getting the things you would need to shoot. But if you could and did, I think you would find the article and the formula to be pretty good when put to the test and pretty interesting in practice.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson