Whilst this is a photo copy, and some of the pages are a little askew, it was all readable and intact. A real bonus finding an old manual for a classic piece of kit that no other site had.
Text excerpt from page 22 (click to view)
Fitting the plinth
Important For the efficient operation of the appliance, it is important that the original ventilation grid is used.
For an opening height dimension A=820 mm and a plinth height dimension a=100 mm, the plinth may be fitted without adjustments. The same applies to an opening height dimension B=870 mm and a plinth height dimension b=150 mm. For plinth heights greater than a=100 mm, b=150 mm, a cut should be made in the plinth, 580 mm wide, in the centre of the appliance position, leaving a remaining height of a=100 mm, b=150 mm. Attach plinth to the kitchen units. Important The plinth must be positioned at a minimun distance of 25 mm from the door.