My bandsaw blade loses its edge on the inside of the blade first resulting in cutting at an angle. I can only overcome this by feeding wood into the blade at an angle. Is the setup at fault or have I blunted the inside edge on something hard?

The blade usually performs in this way if the set of the teeth has become damaged or worn on one side. The guides may be set too close to the teeth causing damage or the blade may have worn naturally if you have been cutting curved work on a regular basis. The best option would be to start by replacing the blade, but make sure that all blade guides are well clear of the blade before fitting, and re- adjust the guides after the blade has been tracked and tensioned correctly.