Sorry, I have no idea how my reply to a completely different thread about luggage ended up here.
I actually wanted to reply to you, regarding work options in Japan with a medical degree. If you are interested in working in pharmaceutical industry or CROs, there might be an opportunity for you there, where you do not need to validate your medical title in Japan. Specially with your Japanese and English skills. The one weak point I see is your lack of working experience as a doctor, as most medical monitors join the industry after having worked several years as physicians. But this could partially be overcome by your skill set in Japanese & English and partially by the fact that you would likely start at a lower level than medical monitor.
If this is something you are seriously interested as a career option, give me an email ( I think if you click on my user name you can send me a private email).
Pharmaceutical industry however is quite a different working environment from working as a GP or in a hospital, and it might be a decision for life. I am not saying that it is a bad, but it might simply not be what you want to be in your life, if you studied medicine in order to treat patients directly.
If you are unsure if this is a career option you want to entertain, search out medical monitor or clinical research associate (CRA) positions in the UK to understand what the job in general entails.
Medical translation in my eyes would only seem to be an option if your Japanese is very good and includes all the medical terms. And it would be Japanese to English only, for which work should be available. This puts you also far from treating patients, and in my experience (working with translators and working myself in pharmaceutical industry / CRO), the later is much more interesting and diverse than translation. And does pay much better ;-)
If however translation is what you want to do, try reaching out to Honyaku center:
https://www.honyakuctren.com/ I have made good experience with their talented translators and interpreters. Transperfect is an other option, a global player on this field. Not always as good as Honyaku center, where it is Japanese / English only.
Enjoy preparing your move to Japan!