I’d be tempted to just suck it up in this case. If EK do cancel your ticket - or ask you to pay the difference at the airport, you’d be out of pocket a lot more than £100. Of course, you could then try suing them for the difference, with the risk of throwing more money at it.

I’ve got a similar issue with Marriott at the moment… I don’t want to risk losing my Lifetime Titanium status by doing a chargeback for £75 for a no-show fee they charged me