Still thinking. Iwama is quite a small place, and quite far from both Mito and Tokyo (from memory). Not impossible from either location, but not something that I'd want to do on a regular basis. The only Japanese university I have studied at is in Nagoya and I don't think it would really suit your needs. Perhaps Peter Goldsbury has some ideas.
Thank you so much for your help. I will be quite flexible in terms of where if it is the right university. Soto deshi in Iwama at the same time wouldbe great, but there are many wonderful dojos which I would be interested to join.
Will contact Peter Sensei as well
Many thanks so far!