Hey Damienapbt and welcome to CS.
Cimbali (http://www.cimbali.com/en/default.asp) is still very much in business and has offices scattered all over the country. Any of them will very likely have the parts you need in stock, and if not they can certainly order them in. If there isnt one local to you most will happily ship the parts to you.
I did a total rebuild on a 10 year old Cimbali M-28 Basic 2-group awhile back (http://coffeesnobs.com.au/YaBB.pl?num=1103091005/1#1). Fortunately theres a Cimbali dealer not only in the metro area here but only a couple miles away, as a result I was able to go over in person and visit them for parts. They had every conceivable part you can imagine on their shelves.
Java "Getting to be well known at the local Cimbali Dealer" phile