I often find myself performing the same routine actions over again lots of times, for instance selected two objects and then centering one of them on the other. So for this I'd select both objects and then from the Align & Distribute dialog box click "centre on vertical axis" and then "centre on horizontal axis". I find myself selecting objects and then going backwards and forwards to click the buttons a lot though.

Is there a way to program a shortcut or preferably a mouse button to perform the alignment procedure? So I'd select the two objects as usual but then click a spare mouse button that's being programmed with a certain action? it would honestly save me a lot of time if commonly used sets of functions like this could be put in a "group" and then run easily with a shortcut key or (ideally) a mouse button.

For aligning Horizontal and Vertical centres at the same time:

Edit>Preferences>Interface>Keyboard --- Object>Align to Centre. 

Click in the Shortcut column to assign a new keyboard shortcut.

There is no 'macro' functionality at the moment with Inkscape.