Just out of interest, Matheous, what makes you think such a move may be permitted? I am genuinely interested, and not having a go at you. I'm always interested when people raise questions to which I think the answer is plainly obvious, to find out how they got their information.
If you had a puncture,you would stop in the bus lane. It's the same criteria as if you were loading or unloading which you can do unless signs say otherwise.Take your scenario one step further,if there was no bus lane just a general lane would you stop on the pavement to change your tyre.? no, you would stop on the road and traffic would have to manouver around you.