Also the throttle cable feels a bit juddery, almost like its gunked up - I plan to check the routing just to be sure its not kinked anywhere, but is it possible to just put a few drips of oil down the ends of the sleeve to lube it?
Don't rush out and buy a new throttle cable, as I and others have done, only to find it makes no difference. Troubleshoot it thoroughly as it could be the throttle body or (more likely, I think) the pedal, especially the bushes.
See this post.