In addition to offering many different types of mortgage, a mortgage lender will also have the resources to help you find the best product to suit your financial circumstances. When you are looking for the best mortgage, you should consult an independent adviser if you would like to have access to the whole of the market, because obviously a lender will only promote their own products to you.
All mortgage advisers should be authorised by the Financial Services Authority (FSA), the governing body for the financial services market. You should always use an authorised adviser, for your own protection in the case of a dispute, and also to ensure that you are getting correct advice. You can check that the adviser you plan to use is authorised by looking them up on the register available on the FSA website, or consulting a directory on the website owned by the Council of Mortgage Lenders, the trade association for the mortgage industry.
If you are looking for a specific type of mortgage, do your research and find a provider who specialises because you will get much better deals this way. For example, if you are looking for a commercial mortgage, don't choose a residential lender with a few commercial products because you recognise the brand when a commercial lender will have a much wider variety of mortgage packages. Likewise, if you have less than desirable credit, don't necessarily choose a mainstream lender because the lending requirements will be extremely strict and you will not get a competitive interest rate. Instead, search for a lender that provides bad credit mortgages, because their terms will be much more tailored to your circumstances.