Ukranian potential tenant - guarantor, references etc

Guarantor

HI

We are in the process of renting out our London flat and have had a Ukranian lady with one teenage child applying - she is willing to pay 6 months of rent upfront and apparently has a person who could act as guarantor. However, she currently does not have enough actual employment income to cover the rent (though tells me she is applying for UC and will be getting some sort of student support plus has savings/support from relatives). So far she has been staying with friends and does not have a UK landloard to provide a reference. 

I think if we go ahead we have to essentially treat her like a student. Any ideas how to obtaing mainingful references? Any specific landloard insurance that you would recommend in these circumstances? Or shall we just run a mile and keep looking for someone more suitable (her advantage are the up-front rent, ability to move asap as staying with friends and she is happy to rent the place with current furnishings) 

Thanks for your advice