Even so, you can do some back of the fag packet calculations.
Starting with , 1 in 3 people you meet won't vote. So they can be safely ignored. Doesn't matter how passionate or vocal they are, if they don't vote, they don't count.
Growing up our neighbour was a bit of a working class tory. With a lot of views. Only his wife let slip to my DM he never voted. Didn't know how to. Meanwhile she once slyly voted Labour while taking her grandaughter to nursery.
In the 2019 election, I was fascinated to see a very elderly gentleman casting his first ever vote. He was asking the officials if he was doing the right thing putting it in the box. Election etiquette prevented me from chatting, but I remain fascinated at what had prompted him to vote so late in life.