I've counted votes a couple times before and can tell you that where I come from in the US recounting is minimal (if done at all). We pair up with a person of our choosing and then count and recount. Collusion is trivial. Just make sure the total counts add up and that your results aren't so wildly disproportionate from the other people's that they'd get reexamined when all the pairs' numbers are summed.
I don't know what you mean by scrutiny on the TV - are local polls counted live on television in the UK?
It's almost impossible to imagine that someone could bribe that many people to influence an election in the UK. There are 650 seats with over 100k population per seat. I just can't imagine it being bribable on a large scale. Maybe some tiny constituency in a tiny district might get influenced, but the absolute smallest is about 20k votes. That's very difficult to rig.
But you don't have to bribe 100k people. You just have to bribe/influence 50,001 people (and I know that's not exactly true, this is based on a US two party system, not the variety of parties in the UK, but hang with me here.) And in reality, it's as the saying goes for Baseball. "Every team is going to win a third of it's games, and every team is going to lose a third of it's games, it's what you do with the last third that makes a difference."
Every party is going to have a large number of supporters and a large number of detractors, it's what you do with the unaffiliated votes that matters.
Now I'm really going to talk out of my ass, in a horrible, gross generalization with no support to back me up; I'd guess that for many elections, it's less than 20% of voters who actually decide the fate of their country/district. And since we're talking about voters (not citizens or residents/people), we're then talking about an even smaller group of people you must influence. That's why bribery, voter intimidation and pure old fashioned marketing matter; You don't need to get everyone on board, only a much smaller percentage of key voters. Isn't democracy great?
I don't know what you mean by scrutiny on the TV - are local polls counted live on television in the UK?