Positioning/deadheading into an English airport as part of a duty/travelling into "
the United Kingdom in the course of their work or are otherwise required to travel to the United Kingdom for work purposes"?
From what I've heard the website you referred to covers it, though it might be worth having a roster/proof of next duty handy...
https://www.gov.uk/government/public...k-border-rules
Section headed:
"Aircraft Pilots and Crew"....