NoD
Because the Flt Crew decided too... [sic]
Actually they were told to. As it happens a BA Airbus had some technical problem that prevented them fully clearing. I saw 2 aircraft carrying out ATC-instructed go-arounds (I thought an EI and a LH, but may be wrong), followed by one (I think) A340 do a visual switch to 27L, before 27R was made available again to landing traffic. All this caused a 10-15 minute start up delay at about 1830 local (to me included).
Furthermore, for all you spotters/journos out there, no big deal, no near death experience, just routine events at a busy airport carried out professionally by professionals.