Doing voice work for anything is contingent on schedule, just like any other project. They take nearly as much time to do as anything else. I'm sure he's had plenty of offers, but, unless the recording is being done in UK it all depends on scheduling and where the recording studios are. Disney and Pixar films are all done in the US, so scheduling them is more problematic and requires him to be away just the same as on any film location. Pride was done in a London studio, so it was easy for him to do it. He's said one of the reasons he likes voice work is that he can stay at home and doesn't have to worry about wardrobe and makeup, which means he doesn't have to get up early and is free to carry on with a normal life at the end of the day. They are regular hours instead of the grueling schedule of video projects. He just gets up at a decent time and goes down to the recording studio without having to care about what he wears, much like a regular job.