Problem with Williams games in mame

[LeedsFan]

I've just been tweaking the finishing touches to a cab regarding artwork. Basically the cab uses a standard monitor and so I play vertical games on this horizontal monitor. So I wanted to have cropped artwork vertical games to take up the space down the sides bu nothing for horizontal games, so they would appear just normal.

I set up a .ini file for vertical games with the artwork set at "1" for each setting and also for it to be cropped. All vertical games now display how I would like. All horizontal games display full screen with no artwork.... except for the Williams games! These games now appear reduced in size in the middle of the screen. No artwork, but like a huge black bezel round the game. It happens on Robotron, Moon Patrol, Defender, Joust, Bubbles.....but strangely Smash TV is fine. 

Any idea what's happened?