A small handful seems about the right number to me as well, though I would add a few more. But as always it is more complicated than that. I consider myself to be left of centre. But in the not too distant past I have voted for Conservative, Liberal and Labour. Having said that it is also not really accurate to consider me a floating voter either. In the case of the Tory, for example, in Tony Blair's first season my local MP was Labour and he voted along with the party on every single issue: I may as well have elected a rubber stamp for all the difference it made. The Tory he had replaced was on the centrist side and had proven to himself to be active, concerned about and generally involved in the constituency both as MP before Blair and as an ex-MP after. Also as an MP he had shown himself generally loyal to his party but voting against them on some issues, demonstrating some independence of thought.

So I was left with having to decide between them and on balance I went with him.

And that illustrates the problem, really. Overall, a person's centre of gravity, as it were, may be to the left or right, but anyone can be Left or Right on an individual issue like those you have named, and when that topic is under discussion they may get called left or right wing in a way that does not match their centre of gravity.

The only solution - exactly like the 'what is folk? question really - is to recognise left/right is a convenient label for some purposes, but to be aware of its limitations and to try not to let a label 'frame' your perceptions.