Mortgage Advisors

Has anyone the name of a good Mortgage advisory company?? I am trying to get information on a mortgage that will be taken out next year as the house we are buying will not be completed till then. One of the problems is that my partner who is the major earner is over 60 and no one wants to speak to us till around 6 months before we want the mortgage.
We only want to get an indication if we will be considered or wasting our time and don't want to wait till the end of the year to find out that we can't get one.
Have tried Moneysupermarket.com, RBS, Alliance and Leicester, Woolwich/Halifax.

Northern Rock tends to be good.