I have fallen completely for these bikes, they are amazingly light and still completely functional and beautiful after sitting for many years. The same guy has perhaps 20 vintage brit bikes including a stunning candy red lightweight single speed, at tleast two Rudge (pre Raleigh) and a Phillips (pre Raleigh)
I am not sure I won't get all of them somehow...
Umm...where do you live? I'm sure there's a lot of us who'd like to relieve the guy of his burden.
As for 28 x 1 1/2" tires: as people have said here, Kendas and Schwalbes are pretty easy to find around the Internet. Harris sells 28 x 1 1/2 tubes, as well, but I've always been just fine with 27 x 1 1/4s.
Look around this forum and you'll find a lot of people singing the praises of the Raleigh DL-1 (a.k.a. Tourist). They're not lying -- it's a fantastic ride. Very smooth and comfortable -- and actually quite fast, with the big wheels and the relatively high gearing of the Sturmey-Archer AW 3-speed. I ride mine to work most days (when it's not raining). The only possible disadvantage is the rod-pull brakes, which are very weak by modern standards, even under ideal conditions, and pretty close to worthless when wet. (Great conversation starters, though.) It's important to keep the wheels well trued -- if they're at all out of round, you'll know it when you try to brake. If the rims are stainless, as opposed to chrome, you're in luck -- on mine, the chrome plating has come off in several spots, making the braking pretty nasty. But the rims in your photo look great! Jump for it, I say.