Execqueries

Hi - Query regarding UK tax for deceased non-resident annuitant of Canadian Registered Retirement Income Fund (RRIF). My understanding is that date of death amounts from RRIF are deemed “paid” to non-resident annuitants, so Canada withholds 25% of the date of death RRIF amount as Income Tax for the year of death. The remaining amount is paid out to nominated beneficiaries (not to the estate), who, in this case, are all Canadian residents. If tax has been paid in Canada, do I need to include the date of death RRIF amount (or the amount less 25% holding tax??) as Income on the UK tax return for year of death (if report whole amount, can any be reclaimed as this would result in the amount being taxed in both countries?) or is the money not deemed "paid" in the UK so it does not need to be reported? What happens re IHT - does the date of death RRIF amount (or amount less 25% holding tax?) need including as part of the value of the estate, as the estate was not a beneficiary of the RRIF? Thank-you.