Actually, I managed to suss this one out.
At some point in the last month or so I got a warning from my anti-virus that tabtip.exe was trying to access some system files and did I want to allow it. At the time I had no idea what tabtip was and so prevented it from access. This added it to a banned list of programs. Now, I noticed that I could use all the tools when using the tablet but not when I was using the mouse, which I thought was strange. Also, the tablet input panel whilst visible docked on the side of the screen couldn't be opened. Remembered about tabtip, looked it up and it is an essential system file for tablet use. Re-enabled it through the anti-virus and it magically started working via mouse input again (and I got the tablet input panel back). No idea why it should have killed some of the tools via mouse, but all sorted now.