The mortgage market is highly competitive and can be hard to understand. Getting advice from a qualified and experienced mortgage advisor provides you with confidence. Full research of this field requires effort and time, which can become a full time job, which you probably already have.
Let me worry about the best option for you. Finding the perfect house should be a fun experience, certainly not full of stress.
Getting advice also helps you share the responsibility, avoid making mistakes or being rejected by your chosen lender. Moreover, sometimes we have deals with lenders that would not be available if you go direct and the best part you will not have to fill out all the boring paperwork.