The report you linked to is on a website for "credit professionals" and is about the problems faced by people in debt who had contacted a debt advice line, not people "living in poverty". 47 pounds is about 73 US dollars.
The average CCCS client in London had a monthly shortfall of £47, compared to an average surplus of £44 across the UK.
That's the average difference between what these people get and what they need to meet all their needs and service their borrowing, which leads to them (the people who contact the advice line) getting in debt. It doesn't say anything about the absolute levels of income. It doesn't mean they are eating scraps out of trash bins and their kids have rickets and are running around with their arses hanging out of their trousers. It probably means they let the credit card bill slide after paying for clothes, groceries, iPhone plans, rent or mortgage, cable TV and filling up the car.
The report also says that those contacting the helpline had an average unsecured debt of £17,031, that's $26,000 dollars. That's people contacting a helpline because they are unable to manage their debts, not London people in general. The figures were obtained from 11,000 people who contacted the helpline. The Greater London urban area has a population of around 8.25 million.
In a spirit of web enquiry I did a little search myself and found:
In the US, in 2012, average credit card debt per household with credit card debt: $15,956. That's the overall average debt, not the average debt of people in trouble. These will likely have bigger debts.
33% of Americans do not own a credit card.
54% pay their balance in full each month
33% carry balances up to $10,000 (median balance: $2,254)
13% carry balances over $10,000 (median balance: $17,366)
U.S. consumers racked up an estimated $51 billion worth of fast food on their personal credit and debit cards in 2006.
What that report conveys, then, is that Britain is an average aflluent Western nation, and its citizens are about average. Also the cost of living is a bit higher in London than elsewhere in Britain, (where, Americans tend to forget, another 52 million people live).
As for the TV documentary, I didn't see that.