What sort of financial evidence would a mortgage lender require?

What forms of evidence would a mortgage lender ask you to provide in order to prove:

1. Your salary
2. Your deposit

The reason that I am asking is that I usually pay the vast majority of my monthly earnings into my partner's account each month, as she deals with all of our day-to-day business and savings. Due to slightly adverse credit on my partner's part (and a much smaller salary), I'm going to be applying for a mortgage on my own in order to get a better rate.

If the mortgage lender were to look at my pay slips only, there would be no issue . If they were to look at my bank statements, they would show that almost all of the money I'm paid goes straight out of my account as soon as it goes in, and I'm concerned that this may raise doubts over the legitimacy of my earnings.

Secondly, I am the sole shareholder of a small company (in addition to my employment) and will be raising the money for our deposit by issuing a dividend when it's required. I'm curious as to whether the mortgage company will ask for evidence of this in advance. If so - what are they likely to ask for?

I appreciate any help.

Thanks