Can someone please confirm that it is still possible to arrive from a red list country (SA) and transit airside at LHR to a non-red list country? Yesterday the transit requirements were

i) arrive and depart by air; and

(ii) have a confirmed onward flight departing the same day from the same airport; and

(iii) hold the correct documents for their destination (e.g. a visa for that country if required)

Heathrow's website says - "‘Red list’ passengers transiting via the UK do not have to quarantine if they do not pass immigration. More information can be found on the UK Government website." However, the link cited has no information regarding transit and is no longer valid. I called British Airways, our carrier, to inquire about transit restrictions and the agent emphatically stated that transit passengers ALSO had to quarantine, or were not allowed to transit airside if from a red list country. We argued for some time - I plan to call back and speak to someone else but am too tired right now.