Or you might want to consider this one, even if you don't want to go topless.
It is also lhd, and a better handling 4 wheeler to boot.
It comes with a complete and unrusted chassis, suspension, brakes and everything else still attached, except the drivetrain that you presumed already have.
The body has been stored indoors in California, as someone stopped short of making a convertible out of it, so has completely unrusted floors, and most everything else.
Stuart's seller also has a spare roof and left side glass for sale off eBay, so all you would need is the right side flat glass and windshield (new for about 70 gbp), and you would have your funabout, with your original parts as spares.
Shipping from Los Angeles is considerably cheaper than the other way round, and the car could be shipped as a roller.
Better yet make a holiday of it , bring your tape measure and camera, and you can help me lift off the FF3 body shell, and put the chassis back underneath this Isetta body. Of course I'd put you up for the week, and even give you a newer reliable Cadillac to cruise around the Southern California car attractions for the week.