Thanks for your comments guys.I was last there in 1983 in winter.
I don't know how I forgot this but my nephew lives in Tokyo and is married to a Japanese lady.
(We're not a really close family and my brothers and sisters are all over the place)
Got my sister to email him to ask him to arrange accommodation in Tokyo. He speaks Japanese and has lived there for 11 years so I think he'll come through.
I got over 200 yen to the Aust. dollar in 1983, it's now 92 yen so things won't be cheep, but money is worthless unless you spend it.