If both salary and dividends are regular, the banks will be able to factor them into their calculations
If you are self-employed or a limited company owner, banks will accept salary and dividends as your personal income as long as they appear on your personal tax return. It is common for self-employed people who own a limited company to pay a smaller salary and tax-efficient dividends (although some of the schemes are changing in the UK).
If the lender can see both salary and dividends as regular payments, the banks will be able to factor them into income and affordability calculations.