No luck with a part number from the reconditioners; so lets see what we can find using this photo of the business end of Bobs starter.
There seems to be a distinctive cut out to one side of the upper mounting bolt hole; any vetus owners know if that is required to clear something on the engine?
http://i657.photobucket.com/albums/uu293/eeyore_boater/20130626_1138102.jpg
(Had to change to a link, as site objected to me posting the image direct from either Dropbox or Photobucket. Says that the extention is not allowed on this forum?)
This according to vetus is the later starter.
It has a vetus part number of STM9973 (from vetus website), and a mitsubishi part number of 31B66-00101 (from mitsubishi parts catalogue Nov '07)
The engine backplate and flywheel remained the same after the starter change, so the earlier starter should fit.
It has a vetus part number of STM7964 (from vetus website), and a mitsubishi part number of 31A66-00101 or 31A66-00102 (from mitsubishi parts catalogue Nov '07)
The earlier part numbers produce the largest number of search results, but as prevoiusly posted the cross references are very diverse/unreliable. There is however a recurring reference sugesting that the early starter is likely to be the same as fitted to the previous mitsubishi K4 diesels. Some evidence to support this comes from the fact that the clearance between the starter and engine block varies, the later one has room for fingers, whilst the other does not.
Hope this is of use.
Steve (Eeyore)