[OllieB]

YES! Using a mouse solves the freeze problem as already confirmed by others as well.

However,
- with Deep S4/S5 disabled,
- wake on Lan disabled,
- Enhance IR enabled,
- UEFI boot disabled

I am still NOT able to wake up the NUC with my remote. Powering off works with the remote so I am fairly sure that the remote functions (I am using the Xbox 360 media remote). I have also not been able to restore displaying the NUC logo screen which means I have to guess when to press F2

Any further ideas

Did you CHECK "wake system from S5" ? (I assume so, probably not applicable anyway if you have deep sleep disabled).
Have you tried running irw to make sure the power on command is being sent from the remote?
http://wiki.xbmc.org/index.php?title=LIRC

Checking Wake system from S5 is NOT checked but as I am not using deep sleep S4/S5 I do not think that this would be related.

Yes I have used irw to check that the power button sends a command and yes it does (also demonstrated by the fact that I can power off the NUC using the remote). The information returned by irw is:

74 0 KEY_POWER devinput
74 0 KEY_POWER_UP devinput

I have noticed that the remote device is not listed in /proc/acpi/wakeup as a device that is enabled for S3, this is something I was reading on the internet but I am not sure this file is still used under openelec