Well the problem I faced wasn't with the lease company- they were happy to order the Fiat for me (so I guess they weren't too worried about the residuals). I 've also seen mixed feedback about the Fiat dealers - there are some bad ones out there and also some good ones based on people posting to this forum. Fiat however aren't really in the picture in the UK for company cars though, and if you look at it from a dealer perspective, that means that the lease company will order a car from the dealer who gives them the best sale price. That dealer will probably never see the car again. In a similar vein, the Fiat dealer close to the person who gets the car will see all the warranty/service activity without having seen anything from the sale of the car. Also, as tboneman shows, lease car orders can get changed/terminated at relatively short notice, and if the manufacturer is having to build to order, and then sees the order cancelled, they will be thinking whether they want to risk building the car in the first place (just in case the order is cancelled and they can't then sell that specific build of car to someone else). This is what happened to me with Fiat twice refusing to build the spec I ordered before finally agreeing!
Peugeot, and for that matter Citroen, who are both more established in the UK fleet market, would I suspect have less of an issue with an 807/C8 ordered as a lease/company car, even with a non-standard set of options, and because they deal more with fleets in the UK would probably have less dealer channel reluctance to deal with a lease car as they are more used to doing so!
Of course all this is hindsight as I hadn't looked at the situation to this extent before making my choice, however the after-sales logistics were less of a concern as I chose the one that would give me the most car for what it'd cost me in tax, and at the time that was the Fiat! If you're stuck with a car for 3 years, you want one that is not only comfortable/fun to drive (which they all are), you also want the one that has as many of the available creature comforts as you can afford for the minimum ongoing financial impact (which at the time was the Fiat).....
John
New Fiat Ulysse 2.0JTD Eleganza, with options! 
