Thanks for all, My concern now then would be the interest amounts>
If the interest earned on the original 20k contribution is left in the account - does that interest also figure in the following periods interest calculation?
If so, how does that figure in the UK tax such that it is then a taxable amount or a non-taxable amount? i.e. the interest on the 20k is non-taxable, but the interest on the earned amount is taxable (or not?)