thanks for the tips guys, I got sorted yesterday at Lemon Camera in Ginza (we were visiting Ginza yesterday so it was convenient). They had an impressive range of rangefinders, lots of Nikons and cabinet after cabinet of Leica, not so many Voigtlander products but some unusual stuff (including a very wide bessa with twin lenses?).
I got an LH5 vented hood for just over 15 quid and a VL-1 case for my heliar 15mm and finder for about 12.70. How are the prices? Wasn't too worried about price, products aren't available in Shanghai.
Getting the case for the VL-1 took time.
"I want to get a case for this lens" guy points at standard lens cases on counter
"but I have the viewfinder as well" the guy suggests buying two.
I take him over to the Voigtlander cabinet and point at the VL-1, he says "no, this is for voigtlander", I show him the logo on the lens.
He says "but this is for the 15mm lens", I show him the logo on the lens
Anyway, got there eventually.
I'm really pleased with the vented hood, I'd been using a screw-in "Leica" vented hood from China (extremely cheap but all that was available locally at the time), the lens cap kept falling out, the LH-5 is extremely sturdy and the lens cap goes straight through to clip onto the lens, well worth the money I think (and it looks great)
I'll probably check out the other places in Shinjuku at the weekend, hoping the rain stays off a bit so I can get out and take some pics.