So I've had a Canon 7D for about 3 years. It's started to develop what seems like a lot of trouble with the autofocus over the last couple months. I don't recall having any such issues in the past, but the camera sat mostly unused for about a year until I picked it up again recently.
The autofocus seems to hunt around a lot before locking on, and at infinity it rarely finds focus at all, instead just hunting back and forward aimlessly. This issue is common across all my lenses.
What can I do here to fix the issue? Does it simply need cleaned? Serviced? Is there somewhere I can take it for repair? I'm based in central London.