I tried the Arcade Perfect Utility and it doesn't support the ArcadeVGA 5000. I e-mailed Andy at Ultimarc a got this response.
"Unfortunately we are not able to support the Arcade Perfect utility any more as ATI will not supply the necessary info to permit setting of the clock speed on the HD5450 chipset.
This is a pity but to be honest the number of downloads of this utility was around one per month so it was very little used."
So as a last roll of the dice I tried Powerstrip and it worked
It recognised the ArcadeVGA 5000 and I was able to use the advanced timing options to adjust the screen and save the setting for each resolution.
I tried Rastan with Groovymame, however copying the Powerstrip timing string into the mame.ini and saving as "rastan.ini" the image was centred, but had tearing!
So I deleted the rastan.ini and when I loaded Rastan again I expected it to be off centre, but it wasn't and there was no tearing
Rebooted my machine to the frontend and tried again and Rastan was off centre. Then realised this was because I had shelled the frontend and Powerstrip hadn't loaded.
Added Powerstrip as a pre emulator command line so it was running and all the games are centred, so long as I had saved settings for that resolution in Powerstrip
The only thing that has confused me is why copying the same timings to the Mame.ini caused tearing?