Christopher Jeavons

I am a UK citizen who left UK 23 years ago, thus no longer a UK tax resident. Currently I am a tax resident of Japan As I am now approaching 60, I understand I am allowed to have my UK private personal pension, acquired during my time in UK, paid out as a lump sum. I understand that UK pension rules are that 25% of the lump sum will be tax free and the remaining 75% will be taxed at the emergency tax rate. I am told by the pension company that they will withhold and pay tax to HMRC at emergency tax rate on the 75% of lump sum. As I am a Japan tax resident, can I claim back all the tax withheld by HMRC ?, - What is the process to reclaim the tax withheld? Help and advice will be gratefully received.