Offices usually have many numbers in the same range (i.e. starting with the same few digits). I have found two such entries:
Royal Mail Response Services 0845 795 0950 0161 874 8137 Enquiries relating to creating Freepost and Business Reply accounts including generating artwork
Royal Mail 0845 795 0950 0161 874 8137 PO Box enquiries
I note that the recording on 0161 874 8237 refers to 08457 950 950, which is the published enquiries number for Royal Mail business customers.
Unfortunately 874 8137 answers with a recording "I'm sorry, you have dialled an incorrect number." A try of a few other numbers in the 874 81xx and 82xx ranges gets the message "We are sorry your call has been disconnected." I have removed these two entries.