In the task which involves stacking cans while saying the names of countries, one of the places mentioned by Bob Mortimer is Greenland. Strictly speaking, Greenland is not a country, but a territory owned by Denmark.
Source: Series 5, Episode 5: A Wind-Dried Puffin
"Burst an entire roll of bubble wrap" was a task attempted during each of the first three series, but it never made it to air as it was decided it didn't make good viewing.
The house is a former groundskeepers' cottage inside the grounds of a golf course in Chiswick (West London).
The comedians film their tasks on different days. Sometimes months apart. The producer told Radio Times: "Obviously we have to work around their availability and our availability. We've had some people do it over the course of a few months. We have a handful of dates for each person and then it depends on their availability and our logistics. Vicky, our production manager, has this weird hotchpotch jigsaw of how people's availability sits in with each other - and with us. Mel Giedroyc actually did hers in pretty much a week but Bob Mortimer did a big batch at the house at November and then we did his exterior location tasks in May or April. Quite a few flowers came out in the meantime."
The contestants always wear the same outfit when undertaking the tasks to help with continuity.
There is more trivia about how they make the show to be read in this Radio Times article
In the studio, the comedians are always seated in an alphabetical order, based on their first names.