UK APD is a bit excessive. Some areas of the UK have lower amounts, in order to get people to travel there. They made some changes to the system a while ago, changing it from 4 distance bands to 2 (distance is measured between LON and the capital city of the nation you are traveling to). It's 1 rate for the "lowest class of service" and another, close to double, for anything else.
If you fly from the UK to western Europe to pay lower APD, remember it is based on connections. If you fly LHR-SIN with a connection in AMS, APD is based on going to SIN. If you spend at least 24 hours in AMS, the rate is based on AMS.