I think it wuz just dumb luck on my part.
I was smitten by the V11 Le Mans when it was introduced in 2002 and decided to buy one. I looked up Italian Guzzi dealer phone numbers on the web and started making phone calls. I avoided a dealer in a big city such as Milan, reasoning that negotiating traffic would be much easier in a smaller city. I don't remember if it was the first or second place I called that had someone who spoke English. Told them whut I wanted and they said, "C'mon down."
When I got to the dealer, I explained that I wasn't an E.U. resident and would it still be possible to purchase a bike. Much head scratching and speaking in Italian ensued. To this day, I'm still not sure if laws were massaged or circumvented or what but, I got my bike

They also agreed to store the bike for me so, that solved that problem. I think I pay about 300 Euros a year for insurance.
Buying my Thruxton was fairly straightforward as my friend, who I met online, stores the bike in his garage. Getting insurance in the U.K. might be tricky as many insurers require that you be a resident. Somehow, Footman & James agreed to insure the Thruxton for about 150 pounds a year. I've read online where some Americans were refused insurance for being non-residents. Again, maybe dumb luck on my part.
You also need to get the bike inspected every year if it's more than 2 years old. The bike shop in Italy takes care of the Guzzi while, my friend in the U.K. helps by showing me where to take it. You also need a U.K. road tax disc which is about another 40 pounds(?). U.K registration renewal can be done online and I think it runs about 100 pounds (?). Maybe the Brits can correct me if I'm wrong

I would suggest aiming for a small mom & pop dealership as, they might be more inclined to accomodate you than a large, faceless big city dealer. Maybe I'm being partial in that I believe many Guzzi shops in Italy are mom & pop operations who exist for the love of the brand or for motorcycling in general. In Italy, you seldom see a Yama-Honda-Kawa-Guzzi shop. It seems more often than not, they're a small one brand operation operating on the outskirts of town.
At least, that is my seat of the pants impression
mototouring in Milan also offers storage for 350 Euros a year and, I think they offer basic maintenance services such as oil changes, or they used to.