Definition of working in the 'security industry'

How would a person define as to whether or not they work in the security industry?

Their title is not that of a security officer, however, they patrol a specific area, request trespassers to leave the premises and encounter unsocial behaviour (drugs and alcohol) on a daily basis. This role also has other functions such as dealing with customers, taking cash payments etc. but what defines a person as being apart of the security industry?

The reason I'm asking is that aren't the security industry entitled to premiums such as unsocial hours?

Also is there any case law available of a judgement on whether a person was deemed to be a security worker through their role rather than title? I've checked Balii but to no avail.

I would consider the above to be the role of a security guard but it will be interesting to hear the opinions on this.