During the emergency briefing prior to departure, it is quite normal for the Pilot flying to brief that, in an emergency they will return to the departure airfield. Indeed, to that end they will both normally have the approach plate easily accessible to facilitate just that scenario. Poor weather, difficult terrain, likely contaminated sole runway, or other significant performance limitations would also sensibly require the nomination of an alternate airport. Heathrow (usually) has none of those considerations, and its use to facilitate the emergency scenario is perfectly normal.
What may be "desirable" for ATC, homeowners, daily mail readers, or anybody else is entirely secondary to the aircraft commanders intentions in such an emergency scenario, as indeed your quote makes clear.