UPDATE!!
The nice man approach worked first time! The photo's have been removed and I'm now a happy man. Thank you for all your help, speculation

and advice. Having researched the links
I am confident I own the copyright and stated as such and it's had the desired effect.
Fankkk ooooo!!!!
Yes, if they are an employee, you do.
As a reference for other folk who may wonder about who owns their 'work' photos, the law is quite clear. Simple definition of an employee is somebody who has their tax and NI paid (so this
does not apply to freelances). There are other definitions, but that's an easy one.
Anything they do in work hours pretty much belongs to their employer. Anything they do in connection with work, outside work hours, quite possibly belongs to the employer also (depends - bit of a grey area). I have had cases like this which have gone legal and even the stuff done outside work hours belonged to us (employer).
Normally, it would therefore be down to the employee to prove that this was not the case, and unless they had negotiated a specific clause in their contract, it would be quite difficult.
If the guy used his own camera you could end up with a silly situation where the employer owned the image Rights (the intellectual property) but the employee owned the 'materials' which in effect would mean the digital files. In other words, the employer might own the images but couldn't access them, and the employee could access them but could not use them! That is usually sorted out with an exchange of cash, or a court might make a ruling.
I guess the message for people on here is that if you are an employee and take photos in work hours, or outside work hours but in a related area (this is quite common) then either you don't own the pictures, or at best your ownership would be in serious doubt if it ever went to court. Of course, as always 'possession is 9/10ths of the law'

but if you want to be sure, get a clause added to your contract sooner rather than later.