Were moving back to the UK in the new year. My oldest son and his girlfriend will join us until september when she will return for uni. They both hope to work and travel while with us. my son is a citizen but his girlfriend is Canadian. trying to see what visa to apply for.
any help would be great.

Canadians do not require a visa to visit the U.K. up to 6 months.

She wants to be able to work while she is there.

Well she wont be doing that as a tourist.

Maybe get her to research what possible visa she could use.

well presumably that's why the OP came here to BE!

OP just a quick glance but this looks like a good option.
https://www.gov.uk/tier-5-youth-mobility

the other visas are listed but if she is 18-30 yrs old and has £1890 this seems to fit the bill. Gives her 2 years.

Thankyou soo much, just had a look, and think that fits perfect.

Are any of her grandparents British? As she would be eligible for an ancestry visa.

Any recent European ancestry? It may make her eligible for an EU/EEA passport to bypass the need for a visa altogether.

Her back ground is Mennonite, originates from Mexico. She said she once did one of those ancestry checks and it said she was 6% European. but maybe worth asking more.

My cousin married a Mexican-born Canadian Mennonite and started a family in Gloucestershire together. They often originated from the Netherlands or Germany and the chances are any such ancestry will be too remote to be of use but it is still worth asking.