The 'irish' screens were filmed in Hundall & Apperknowle. The pub in episode 3 was the Barrack in Apperknowle , the exterior also featured in episopde 4, don't know the other pub in episode 4. The housing estates in episode 4 looked like Barrow hill / Whittington , but not sure.
The min payment is just that the min payment not to default on a payment , it does not mean you are going to reduce the amount owed. For example Amount owed £ 2000 Min payment required £ 100 Actual Amount Paid £ 200 Amount owed £ 1800 Interest charged £ 300 New amount owed £ 2100 So even if you pay more than the minimum payment the amount owed can still go up and so will the minimum payment . Credit card companies love people who only pay the min payment or less than the interest charged as they will never pay the bill off .