I got this email a couple of months ago. Interesting, because when I was out of the UK I would sometimes get a message saying I'd reached the maximum 20 articles and needed to subscribe. Then, if I logged in from a different location, it would start again at '0' until I got to 20.
When I was in the Uk that never happened.
Then out of UK it would happen again, so I tried to subscribe and it wouldn't accept my credit card because it wouldn't accept a UK billing address for a UK credit card when my IP showed that I was in a different country. The option to change country was fixed for the country I was in at that time (Poland).
In order to be able to continue reading, I found a sneaky and dishonest way of temporarily bypassing the '20 articles' rule, as at that point there was no other choice.
Since then, I've never run up against the problem so I wondered if they'd abandoned the idea. Their site won't let me subscribe until I'm actually in the UK, apparently ......... so ...! Oddly enough, I'm quite happy to pay for access, but it won't let me.