Moving belongings after the permitted 1 year. Tips?

I was surprised to learn there's a one year time limit on moving personal items to Japan from the date you arrive/get your visa.

Removals companies are flat out saying no. I've been recommended DHL and so want to check in what others have experienced or recommend?

I don't have a huge amount. ~200kg. From the UK. I've been given a ballpark figure by DHL and what customs and taxes to expect, which is more than I would like, but I'm willing to do it.

My concern is with the customs side of things and so I'm hoping others can share their experiences so I know what to expect, tips and can prepare accordingly.

Thank you!

by jupetoh