Like any town, in Swindon you have a choice of people who can help you buy your Home.
Independent Financial Advisers (IFA): Whole of Market advice on mortgages & insurance, think of them as Mortgage Advisers offering a greater range of services.
Estate Agents: Typically a panel of 10-15 lenders. Not whole of Market Insurance, tied to one company. Sold to you by a youth with gelled hair & a large knot in his tie.
Mortgage Broker: Check if independent, whole of market. Offers insurance from one insurer or limited range
Banks/Building Society: only offer their own limited range of products for mortgages and insurance.
Hope the differences betweeen various kinds of mortgage advisers is clearer.