Cheers chaps - it did turn into a little bit of a hunt especially for controls.dat, but got them all in the end.
So all done as directed, but not launching from GE.
Launch fine from MAME directly, also from lifted command line form log.txt. HOwever, when launched from GE, just tries an returns immediately to GE. No clues that I can see in the log either...
On a positive note - game descriptions are now right (albeit all now prefixed with "a ## year old game" - that gameex or one of the dat files?)
Any advice appreciated! I think Mame is my nemesis weirdly...
log.txt
GameEx.ini