Time apportioned reduction

[IPTM3730](https://www.gov.uk/hmrc-internal-manuals/insurance-policyholder-taxation-manual/iptm3730) talks about relief that can be obtained if the policy was held by someone who was not a uk tax resident and subsequently became one after which the policy was redeemed (disposed off). It specifically highlights foreign life insurance policies and "foreign capital redemption policy". I want to confirm if the treatment is the same for other portfolios which result in a gain when disposed off. E.g If I had investments in an Offshore Non-Reporting Mutual Fund before becoming a UK tax resident and then subsequently became UK tax resident and then disposed off the funds (closed the account and collected all the proceeds), how do I calculate the Offshore Income Gain for this? Can I get time apportioned reduction on the gains realised? For e.g if the non-reporting offshore mutual fund was bought 10 years back, I became a UK tax resident 5 years back and I disposed it off today and realised a net gain, can I get a reduction of 50% on my Offshore Income Gains Liability since I was only 50% of the number of days in the UK compared to the period since when I held the Mutual Fund?

Hi ustulation,
Please refer to guidance at:
​​​​ Temporary non-residents and Capital Gains Tax (Self Assessment helpsheet HS278)
Thank you.