You really expect MINI to replace entire stock assemblies that you've removed from the car?
I had a similar issue - wipers disintegrated in Kansas on a cross country trip. I bought a set of Trico wipers and tossed the OEM in the boot. I forgot to put the OEM on the car at the next service, they graciously gave me just the inserts (and replaced my rear wiper) so that I could install them at home. Now I've got a backup pair.
The wiper replacement policy seems pretty reasonable - to expect them to replace the assemblies seems over the top.

 

They didn't graciously give you the wiper blades. They are part of a prepaid service that is a part of the purchase price of the Mini.

In our case we still had the assemblies but we didn't have the metal strips that go the length of the rubber blade as those were taken off when we replaced the blades. The Mini service person wanted us to buy the whole assemblies and claimed that the metal strips were special and that they could not use the ones we had with the replacements. They do not provide the metal strips. They only replace the rubber blade.

Anyway thanks for your opinion.

 

Try Vinegar on a clean rag wipe the blade edge. The vinegar is acidic which will dissolve the grease and grime that develops. I use it about every week here in England as the M25 motorway is a totaly filth haven and grease splatters from semi trucks are the norm. Try it... It works.

 

Prestige replaced mine w/o me even asking them to... Now that I think about it my rear blade needs to be replaced as it's starting to seperate. I've had my MINI since late May.