I suggest you try numbers similar to the fax number. A Google of the website for 0116 (see
here) reveals another couple of other numbers beginning 0116 2494xxx.
I would try 0116 2494100, simply because it ends 00 and may be the first number in their block. It currently answers with a message "This service is not compatible with this call".
As chance would have it, the 0845 number answers with the same message......