It doesn't alter the fact that Redhill is not a controlled aerodrome, so that anyone operating their radio cannot ever be called a controller - there being nothing to "control". This is the kind of confusion that I so loathe in UK radio usage, and in UK aviation language in general.
Redhill (EGKR) *is* a controlled airport, it has an aerodrome control ATC service (Redhill Tower), and thus the people on the end of the radios are licensed air traffic controllers...