Nationwide's CEO has been in touch regarding the petition. He put me in touch with someone else to continue to reply on behalf of him. 

Some of the reply said the following:

"As I hope you will understand, in order to maintain our employee Healthcare Scheme effectively, and to enable us to offer it to as many employees as possible, we have to carefully balance the level of cover we can provide. With this in mind, our healthcare provision covers a wide range of conditions and treatments, although does not extend to metastasis. Even if the scheme did cover this, we are unable to fund non-NICE approved drug treatments such as Bevacizumab (Avastin). This is also the approach other healthcare schemes take. "

"We try and make this as clear as possible in our Scheme documentation, which is available to all employees via our Intranet."

"I hope the above context and explanation of the benefits your mum receives by virtue of her long service with Nationwide has reassured you that whilst this is not the outcome you were hoping for, the support Nationwide has provided to your mum has been the best we could possibly offer as her employer."

It most definitely doesn't seem the best support my Mum could be offered and shows they are not willing to fund her treatment. The Daily Mail and other papers are now in touch - we want Nationwide to listen and look at Mum as an individual, not reply with copy and pasted policy notes.