Brian,
do not forget that 'ATCO' stands for 'Air traffic Control Officer'.
A police 'officer' will generally adhere to a dress-code, as will 'officers' in the RAF, Army and Navy.
Dress-code is an emotive subject. When i and my contemporaries joined NATS, a suit or sports jacket was obligatory. Bow-ties were often proudly worn too.
At the unit I 'retired' from, the cleaners and other support staff were often dressed more appropriately than the 'officers' they were supporting.
Not a 'rant', just merely an observation.
If NATS had provided me with a polo-shirt with the company logo emblazoned on it, would I have worn it?
Certainly, even if it lit up and flashed 'NATS', in the dark.