FM
The agreed definition of an Airprox is a situation in which, in the opinion of a pilot or a controller, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved was or may have been compromised
QED, there is no such thing as a 'very minor' airprox.
After investigation it may get rated as category C - ' No risk of collision existed', but thats for the UKAB / SRG to determine and NOT a 'very senior executive at TUI'