Great success (apart from snapping a string when I tightened the strings up again)!
Thanks for the advice Alan.
Alan Ratcliffe wrote
You'd be surprised how low a nut can be before causing problems (basically the same height as the frets).
You ended up being spot on! Isn't an issue.
When I took out the nut I found the reason for the high action was some sort of shim that was between the pickup and the saddle. I took that out, put the saddle back in, measured again and ended up taking 1/32" of the low E and slightly more on the high E.
I'm very happy with the results, playability is soooo better. Also, the guitar rings out (for a lack of a better description) noticeably better. The angle between the saddle and the bridge now looks like pictures online (it was pretty steep previously). During my bit of research I read that a wrong angle can affect the compression (I think) and affect the sound? Is it all in my head or would it really make such a noticeable difference?