*250,000 people are estimated to have attended Elizabeth II's lying in state - 0.003% of the population, again likely to be biased towards those living in London and places where London is easily reachable; and including foreign tourists who happened to be in London at the time.
So, no, not representative, even leaving aside the fact that Elizabeth is no longer a living member of the RF and many non-Royalists had a personal respect for her as an individual which won't necessarily carry forward to her descendants.*
Given that it was necessary to queue for 24 hours plus that would have ruled out people like me who couldn't disappear from work for a couple of days and no doubt many people whose health was not up to an overnight queue. (I still don't know how they managed toilet breaks 
)
A doctor from work went, outing herself as an enthusiastic monarchist - I had no idea, she seems to have managed to attend most of the big Royal events of my lifetime going back to the wedding of Charles and Diana.
My next door neighbour's daughter went, with a friend.
I have no idea how many other people (like myself) would have liked to have gone but were unable to or simply couldn't face a 24 hour queue. Given they were queuing right up to the last minute I assume the whole thing worked to capacity - that is, it would have been impossible for another 250,000 to visit. Maybe if they had kept the lying in state going another week double the number of people would have attended.
So I'm not sure what it is you think you can conclude from your simplistic attempt at statistical analysis.