Mmm. A hand throttle would be handy, I'll have to ferret around for a IIa one.
Fuel tank shedding it's inner lining of rust, I suspect. I've just changed a fuel tank on one of mine as I had problems with fuel starvation. Mind you, not before I'd changed the fuel lines, swapped a carb and fitted another fuel pump. But it kept blocking up the pickup tube, and I got sick and tired of attempting to clean the tank out, after having to remove the tank for the third time, I replaced it with a new one. That damn filler hose on a SWB Series is a bitch.
Alex