I haven't got a '06, but just to confirm...... there should be no issue with supply. Two of the dealers on here, supply the unit. One being a main Nissan dealer...... so why should any of the other dealers have an issue.
Seems like typical, well you've bought the car now, so they in no rush to sort this out. I think you need to get down there and be strong but polite with explaining the situation?
Might be worthwhile printing out the ebay page from Holdcrofts etc as evidence?
And just in case, the ones that we have all purchased ARE Nissan items!