easy Swiss
The replay facility on flightradar24 shows that it left GVA around 12.30 UK time heading for EDI I believe.
At approx 13.30 emergency squawk 7700 was showing near Stansted and descent started from 38000 ft in a holding pattern to the north of STN.
It landed Luton 14.10 approx and closed the airport briefly I understand with easyjet HAM-LTN diverting to Stansted and a Monarch A320 held for about 40 minutes but landed.
EDI departures just showed delayed on the outbound GVA at the time.
The aircraft left Luton today at 13.14 as EZS9002 (empty) but is already back in service on GVA-SCQ.
Pete