Going back to do a Postdoc at 35?
I am currently a postdoc in the UK. My situation is similar to yours: in my thirties, have a family and little children. This is my first postdoc, which I took in my thirties. I also wish to pursue a career in academia. But unlike yours, I have no industrial experience and I am not from the EU. Cost wise, if you and your family are non-EU nationals, you will need to pay a lot more so that your family can stay in the UK with you. Still, regardless of your nationality, it can be a bit hard to support the family if you are the sole breadwinner, but it is not impossible. 

Do you intend to continue living in the UK, or are you open to moving to another country at the end of your postdoc? Your experience of living in different countries plus your industrial experience are an advantage should you find that there are no suitable academic opportunities in the UK after your postdoc. 

What I would think is more important is to have an understanding and support from your wife. As a postdoc, you might have more freedom and flexibility over how you manage your time at work, but the pressure to publish may be high. It is important to know your limitations now that you have a family. It is likewise important for your wife to know what to expect. Having said this, considering you experienced Japanese working culture, what I have just said might not be a problem for you.

All in all, it looks to me that there is nothing for you to worry about going back to do a postdoc in the UK at 35, at least not from the technical aspects above. The deciding factors could be something more practical or personal, but it could be that I have said this from my own limited perspective.