Have a look here at their product literature if all else fails. There is an exploded diagram in the manual (parts 24, 25 & 26 I think).
https://www.narexmte.cz/system/enMTE_vcc2C3_01AA.htm
Drop Narex a line and they might give you a drawing or a price for the missing parts so you can see if it is worth while making them.
If all else fails, find and download the Wohlhaupter UPA manuals as they have line drawings of each part which will give you proportions. You can work out scale from your own device (the stop has a projecting tenon, so you can measure the slot).