Probably. The most sensible option is to wait for Amex to contact you and then tell them that you have temporarily moved abroad and that you will not use your Amex in that time. Amex is cool with this. There is only a problem when Amex tries to send some miles to BA, so ensure you have a £0 balance before you do it.

If the Amex fee is annoying you, simply move to the free card.

However, once you've booked your 2-4-1 travel you are safe even if you later cancel the Amex. This is the most sensible route to take.