Transferring tax-free trust fund proceeds from UK to Japan

I should be coming into a reasonably large sum of money from a trust fund in my and other family members’ names being dissolved (or whatever the correct technical term is) such that if I was domiciled in the UK I would receive the money tax-free. However, being permanently resident in Japan, I will want to transfer the money here.

Will I be taxed on it? Is it better to get it directly transferred from a lawyer (they can, I hope, handle any tax-related questions the authorities might have) or should I put the money into a UK bank then transfer myself? The sum is very likely to be significantly more than the $10,000 AML limit.