Referee ‘Acceptable professional persons’ Clarification

Dear Experts,

My wife is applying for the citizenship and we are getting a bit confused by the 'acceptable professional persons' list for referees.

Could our friend who is a UK citizen software engineer with a masters degree be a referee? I don't see software engineers on the list.

https://assets.publishing.service.gov.u ... als_v4.pdf

The other question that we are having trouble finding an answer for is do both the referees have to be UK citizens?

Thanks in advance for any help you can give!

She needs TWO referees.

One must be a professional of any nationality, ie. someone professional on the list. By professional, they mean someone who is registered with the regulatory body for example and Optometrists would be registered with the General Optical Council, a solicitor would be registered with the Solicitors Regulatory Authority, a mechanical Engineer would be registered with Institute of Mechanical Engineers and the Engineering Council.

Professional in this sense does not mean simply having a degree.

The second referee must be British and over the age of 25.