Thank You Sonic393 but I worked it out myself today. However, your instructions should be posted as a "Sticky" for all the other imbeciles like me....
& furthermore, it is not as simple as you say.
I had to copy my V28 CD to my HDD, make an UltaISO image on the HDD then copy the "Navboot" file elsewhere on the HDD then use NavTweak to open up the "Robotimaps" files on the copied (Not ISO image) V28.Look for the 400 x 234 pixel file (Which if you click on shows the boring BMW logo) then use "NavTweak" to replace the GIF file into your saved "Navboot" file. I then used UltraISO to replace the ISO V28 Navboot file with my saved "Navboot" file & burnt it at 4x speed. A great result - I now have the AC Schintzer Logo on start up.
I did have to reload my earlier V27.1 OS then again reload my ACS modified V28 OS to update the firmware on my Nav Computer - but that is normal.
By the way, I used Navtweak V1 as V2.2 just would not work for me - & I have a state of the art PC....
Anyway, I am grateful for your advice, but to anybody computer illiterate it means not a lot. It's only simple if somebody can produce idiot proof instructions. I was the Head of IT for the F&CO in Bosnia/Serbia a few years ago & as such realise that the "experts" can spout forth about "perl" etc. That means nothing to the average guy/gal on this forum. The expertise is here. All it requires is for an "expert" to put instructions into plain English - which I hope that I have done.........
Mike