However, there does appear to be problems with the installers. I'd like, if possible, to help solve the problems rather than just sidestep them.
An admirable idea, much appreciated here! But that installer has been abandoned in favor of the brand new one in 7.1. So I'd say if you want and can get 7.0 up just for yourself, take the easy way this time. Help is very much needed all the way around, but overthere's suggestion is a good one if you want to do more with installer.
With this in mind can anyone:-
(i) point me to where the X11 keymap list might live
(ii) is there a way I can access the 'Xorg.0.log' file so that I can see what might be going wrong with the graphical installer.
(ii) In that installer, I don't know. You can probably get to a terminal somehow. In the new installer, right-click on desktop for menu. Whether installation or installer, /var/log/Xor.g0.log.