Hi,
Please have a look at CG25330A (
CG25330A - Remittance basis: election for foreign losses to be allowable: TCGA92/S16ZA) which states that you must make an election in the first year you claim the remittance basis & in which you are not domiciled in the UK for foreign losses to be allowable.
CG25330A clearly advises that the effect of S16ZA is to prevent foreign losses being allowable unless an election is made (you become allowable under S16 TCGA92).
It also advises the time limits under S42/43 TMA70 for making a claim.
Thank you.