I'd certainly agree that card counters are a tiny minority, especially in the UK. If they weren't I think the casinos here would take more of an interest in the risk to their holds. Never thought I'd see another at work, but just a few weeks ago I sat next to a guy doing exactly the same as I was - but then I always look for the signs when I'm sitting there (another interesting dimension to the game).
On the bankroll matter, I don't play with any consideration to having a sufficient bankroll. Reason? - I have a real job and so my bankroll is constantly renewable. I adopt the alternative strategy of having a sufficient session "fund" that results in an acceptable risk of losing it all at that session. On entering the HoC I al ways have 40 or 50 units of the table min I'll be playing, and the knowledge that there's a chance (I calculated it at, very roughly, around 20%) that I can lose the lot if I hit an early high count but lose hands. It hasn't happened yet, but I know it will at some stage - I'm going to avoid raising anyone's heckles by saying it's due ! ! !
I suspect the vast majority of amateur players (counters included) don't have a separate definitive bankroll, but play on a session-by-session basis. I hope that doesn't make me "half-baked" in the eyes of the fixed bankroll and Kelly betting fraternity?