There were no departures from 27L between BA762 at 08:17 and 09:24.
Runway 27R was closed from BA762's arrival at 08:43 until 10:46.
So presumably 27L was initially closed for inspection and clearance of cowling debris. Possibly the closure had to be extended because of a lack of fire cover, but we don't know how long it took to confirm that 27L was clear.
The times above are taken from WebTrak and should be correct to within 1 minute.
Talking of WebTrak, anyone got any comments on the curvy approach track of BA762 (see my post #347)?