Accounting for equity instruments
When there is an investment in equity instrument, it is required to measure it subsequently at fair value per FRS109.
It is also required to charge the change in fair value to profit or loss.
You can irrevocably elected to charge the change in fair value to other comprehensive income if hold it not for sale. Any foreign exchange gain or loss be part of the fair value component. It is because the equity instrumen is an non-monetary item.