I asked these questions some months ago when I installed new "tubeless" Vredesteins and tubes on my wire wheels. I got a lot of good information and advice at the time.
1. All agree that tubes in tubeless tires are required with wire wheels, but it is important to install tubes mades especially for this purpose (good quality tubes) and install rim strips or wrap duck tape around the rims to protect the tubes from rubbing against the spoke ends.
2. Many said that old steel wheels present as much of a problem with leaking that wire wheels do and that tubes can and probably should be used in them.
3. It is generally agreed that problems with tubes in tubeless tires occur mainly at high speeds and heavy weight. The main culprit is heat. Since the tire loading is small with a British roadster, however,and since you're not likely to spend much time at 80 mph and above, there probably won't be a problem because there's less chance of excessive heat.
4. Folks recommend 32psi in front and 35 psi in rear with Vredesteins.
Bottom line: You've got to use tubes in tubeless tires mounted on wire wheels and, with these small roadsters and at reasonable speeds and rim strips, there should be no problem.
I'm no expert, but this is what I have been told and have been running tubes in my tubeless Vedresteins for months with no problems.