Colin, am sure Andy (The cern) has put up this link before, worth a try.
http://robush.comP
I doubt that Robush can supply. especially you need the top hat washers and roll pins to do the job properly.
You could try cavalitto in Italy but you need to be patient and use email to ask price for each item. You can order on line but with carriage c25eu you may end up not saving much if any.
https://www.oldlanciaspares.com/742-lancia-FLAVIA-sparepart-silentblock-rear-bar.phpDo not use poly bushes for the D blocks as it will be a harsher IMHO.