It appears the printer went to Court initially with a claim for the cost of the printing. Who was that claim against - was it you personally or your organisation or the Met.? Did it result in a County Court Judgement? If so, the Court fee would have been included in the judgement and should have been paid along with the rest of the debt.
As the Court fee was not paid, the new claim for it (which will incur another Court fee!) should be against the same person/organisation that the initial claim was against. No-one else can be held liable for it. If the initial claim was not against you personally and the printer insists on issuing a claim against you, you should defend it on the basis that you do not owe the money because it arises from a claim which was not against you.
However, it does seem as if someone should pay the printer the �45 as the debt wasn't paid before a Court claim was issued. So the simplest thing is for your organisation or the Met to pay it, otherwise the amount will increase by the � of the new Court fee.