Pretty sure that's a Webtrack error, SWR35B (LX352 GVA-LHR) was already on the ground by this time. No record of a SWR5717 or any other Swiss flights from GVA-LHR on that day around that time on the usual sites. It's not a LHR callsign/flight number that I recognise, nor does it appear on FR24 or other ADS-B tracker sites that I can see.