We found that apertures (when the board was cut to size first) were not central by about 2mm on both X and Y axis.
So I undid all the bolts on the clamps and removed the air solenoids from underneath (they hold on the bars that the clamps cover) then I went to work with my drill.
I thought about putting new holes away from the old ones, but they would have had to have been very accurate, so, instead, I made the existing holes in to slots that allow fine adjustment - a few taps with a rubber hammer here and there before final tightening and .... wallah - apertures perfectly central.

Just kidding
