Since MMR it is certainly more difficult to get a mortgage. Lenders are now looking at all aspects of your finances, particularly outgoings on top of the more common credit commitments such as loans, HP, credit card debt etc.
Lenders are now looking at childcare costs, pension contributions, school fees and other "optional" expenditure when assessing how much money is left over to be used for the mortgage payments.
Most lenders that is. Some factor in 1 of the above, some 2, and some all 3, but there are others dont factor in any.
Knowing which lenders which do and which don't is why you choose a mortgage broker.