Offshore Life Assurance policy drawdown

Crsm123

Hi,

I have an offshore life assurance policy that I contributed to whilst a non-UK resident.  I have since moved back to the UK and contributions stopped.  I now want to cash-in a portion of the life assurance policy.
I understand that I need a chargeable gains certificate.
I also understand that I can withdraw 5% of total contributions for each year from the first anniversary of the start of the policy.
I really want to understand my tax liability (if any) if I take a lump sum.  So for example if I had contributed 100K in the last 10 years and I wanted to withdraw 40K would there be any tax to pay?
I am a lower rate tax payer with only dividend and bank interest as income.

mybestattempt

This may help:

https://www.gov.uk/hmrc-internal-manuals/insurance-policyholder-taxation-manual/iptm3110