Perhaps see if your company will provide a brief letter on official paper with your details and reason for travel, this is what my employer has provided for sim duties etc. in other countries.
My recent experience flying from an amber country to the U.K. was that the U.K. border force were aware of the exemptions but as others have said, airline staff may not be.
Generally the more paperwork you have the better (never thought I’d say that ...)
Expect long queues on arrival into the U.K. ...