So Accor and Hyatt are booking that far ahead now albeit not particularly cheap.
So I've booked:
England v USA (Sapporo) - Mecure Sapporo. This was a non-refundable option but I get the feeling things won't get much better, with Australia and England in town the same weekend and reading some things around hotel availability during the snow festival (another time when Sapporo gets busy). It is also a hotel England Rugby Travel are using on some of their tours.
I've then a few days to sort out somewhere before my batch of Kobe and Osaka games where I have reserved the Hyatt Regency in Osaka - unfortunately a bit out of Osaka centre so will require a bit of a mission with either subway or even a taxi to get back from Osaka station after the Kobe games. I do have an AirBnB booked for Kobe but my confidence level of that booking being kept 'good' by the host is low. At least I have a back up if it does go belly up or don't find something more appealing later down the line.
England v Argentina (Tokyo) - not that bothered about sorting yet as there will be ample opportunity crop up.
So all in all got an accommodation plan at least that if nothing else comes up I can use, now just need to sort the flights in a month or so.