Proof of identity for Government Gateway account

I’ve been assisting my elderly mother to do her tax return. It’s very straight forward just her pension and some rent she receives for some fields she leases to a local farmer. We’ve previously submitted paper tax returns but this year she was told she had to submit on line. The problem we have encountered is that in order to set up her Government Gateway account she needs to prove her identity and the only way she can do this is with previous tax returns and her driving licence. This keeps failing and I think it is because her surname on her driving licence starts Mac (the correct spelling) but on HMRC records it starts Mc. I’ve tried phoning HMRC to try and resolve this but never got an answer. My mother is very hard of hearing. Is there a way this could be sorted out by E-mail or by arranging for someone to call her when I am there to assist her?

Hi Donald Maclaren,
Apologies for any inconvenience caused in asking for an online return.
We can arrange to have a paper return issued, or set up some additional support to help your mother complete her return online.
Please contact us via:
Self Assessment: general enquiries
Here, you can access our webchat service, if you continue to have issues contacting us by phone.
Thank you.