In my experience, "good" estate agents are few and far between.
The bad ones will usually "negotiate" the selling price so as to benefit the buyer. They are supposedly employed to act for you. If you hint to them you may take such and such an offer against asking price, they will disclose that to the buyer. If lower still is offered, then their focus is to secure the deal and persuade you, their client, to accept the still lower offer. T
Do the maths: 1.5% of £500k is £7.5K (+ vat) and of £450k, it's £6.75k. £50k less for you is a few hundred less for them. Losing a low offer, means they get nothing and have to start the whole process all over again or lose the agency rights to a competing agent.
The important caveat is that if you have the good fortune to find the good agent, and there are a few, they will not encourage the buyer to get money off. After an offer is made, they will have the confidence to apply their negotiating skills for you, their client,(not just to secure the sale at the price the buyer is offering) and secure a better sale price.
In the above example, lets say the "good" agent secures a sale price for £10k more than the nervous agent desperate for a sale and scared of losing control. That alone would more than cover the 1.5% fee. Imagine that they negotiate 20k more. The "good" agent is invaluable. They can almost certainly negotiate better than you or Purple Bricks.
On a practical note:
If you do employ an agent and approve their valuation
1. always be
firm that this is the price at which you'll sell (and that accepting anything more than, say, £5k off is out of the question)
2. ask for a discount on the 1.5% fee, relating other agents are doing 1.25% or even 1% and that is what you want. If it's a good agent, don't be too surprised if the 1% isn't available. They negotiate for themselves too! You
may get 1.25% or similar so it's worth trying.
3. ask that the contract does not extend for more than 8-10 weeks (12 would be a max.). Then you can go elsewhere if it doesn't work out. Agents tend to lose interest after a while and prefer the newer instructions.
4. if an agent suggests a
much higher valuation than his competitors (get 3 round), either be very lucky or expect him/her to come back after 2-3 weeks saying that he's tried but it's not worked and the market dictates a lower asking price - you'll still be tied in to that sole agent who's hooked you by an exaggerated selling price