Joint mortgages where one of us is a contractor

Hi all,
I have a permanent job and get paid an annual salary. Let's call it 50k per year.
My fiancee works on a contracted basis for one or three months at a time, but she has been working for her current employer for over a year - they have regularly renewed the contract. Let's say she has been paid around 50k on the year, but her salary fluctuates up and down every month depending on hours.

What options do we have for buying our own home on a mortgage? Can we pool our salaries together for a mortgage or will hers not count because it's not a permanent job? Can anyone advise please?

Thanks!