An estate agent can value the property for you but if you tell them up front that you won't be selling it with them, they won't be that keen (hint, hint!). A lender will require a new application from you because they will need it to perform the valuation which will confirm the value of the property. In my experience (I've worked for an estate agent and a bank), sometimes the estate agent's valuation can be up to 10% more than what a bank valuer would value the house at. However, if you buy the property via an estate agent, they ought to ensure that they have comparable properties that have already been sold for a similar price. In these current conditions, it may be hard for the estate agent to prove.