I am a happy camper.
Thanks to the internet and Jacob I found a Tokyu Hands store. They only had rather small stretched canvas of not the best quality but I at least felt I was getting somewhere, and with the help of my broken Japanese and the assistants broken English I was directed to a wonderful art supplies store called Kawachi. They had everything I needed and more... needless to say I was like a kid in a candy store. What a massive city this is. I am out on my own today, wandering, picking up a few things before heading back to the apartment to get stuck into my painting. Lots to discover yet! The adventure has just begun.
Now I just need to work out the computer system over here until we get our own connection at the apartment in order to upload images and understand what is on my screen!