Mortgage with new jobs, one temporary

Rosie75

Hello, I am a first time poster (and hopefully, a first time buyer) looking for some advice about mortgages, being completely clueless.
I will be starting a new job in September. It is actually with my current employer who I have been with since last September, but it is a permanent contract whereas my previous one was 1-year, and is a slightly higher salary.
My partner is also starting a new job in September. His job is a 2-year contract.
I was wondering whether it will be possible to apply for a mortgage now, or whether we have to wait until the jobs actually start, or - worse - whether we have to be in those jobs for a certain period of time? Does this vary with different lenders? We will have to relocate, so would like to find somewhere as quickly as possible. We have a deposit of around £80,000 and want to borrow around £150,000. My new salary will be £30k, partner's £25k. Also, my partner is 44 - will we be able to get a 25 year mortgage?
I have been looking at the Kent Reliance website and like the look of the 5-year fixed term, but have been unable to get through on their enquiry line. Does anyone else have experience of this lender?
Thanks for your help:D