Tax on SIPP pension for my 13 year olds inheritance

Hi, My son received a lump sum from a pension fund which was from a deceased estate and has been taxed around 45%. He is 13 years old and the forms that came from the inheristance say to fill out a P50Z(DB) which only related to a person who has been working and has a NI number and payroll etc. Does anybody know what form I will need to claim the 45% tax deducted back?

Hi 

The lump sum would appear to be from a trust.  You will need to submit a self assessment tax return for your son, declaring the payment in the trust section SA107.  
Self assessment will gross up the the lumpsum and work out how much tax your son is required to pay.  It will credit the 45% deducted, allowing a refund of the difference.  Check how to register for Self Assessment.

Thank you