It's pretty likely the delay will improve ... they board the flight and then tell ATC they are 'ready' and usually the slot moves up ( especially if the weather improves / turns out better than forecast and restrictions get lifted) .. Keep an eye on the BA app and you'll likely see the arrival time for your flight update .. currently showing 10.34 arrival ( so 55 minutes late )

BA are pretty good at screwing up things for sure , but this one sounds like it's not their fault