On the advice of other forum members (CK/AK) I complained to my local dealer (Fylde Superbikes/Ducati manchester) and was asked to supply photos of flakey parts (engine cases & oil cooler) and of bikes general condition.
The dealer has got DUK to agree to new casings and oil cooler, the bike goes in for the work to be carried out in 2 weeks time.
IMO it is the dealer who should persue this for you especially if they supplied the vehicle in the first place, indeed your contract was with them therefore they should sort it out thats why they are an authorised dealer.
Persevere!