Tax on Lump Sum on Canadian RRSP and completing Foreign Pages

I am a Canadian resident for tax in the UK for the last 10 years. I planning to make a lump sum withdrawal from my RRSP ( Registered Retirement Saving Plan) in Canada. I will have to pay 25% withholding tax in Canada on the value of the RRSP but believe for UK tax purposes this is a chargeable event. Is this correct ? The gross value of the RRSP is 50,000 GBP with a gain of 20,000 GBP , this having been built up over 10 years. I believe I need to enter 20,000 GBP in box 43 in SA 106 and 10 (years) in box 44 - is this analysis correct ? if not where do I enter the 20,000 GBP. Finally it is my belief that the 25% withheld by Canada cannot be used to reduce any UK income tax due on the 20,000 GBP. Is this correct ? Thanks

Hi,

That is correct.

Thank you.

Thanks for the note .