I’ve paid my holding deposit for a flat that was incorrectly advertised. What are my rights? (England)

So, I’ve been flat hunting recently, and I was shown around a rather nice place that I quite liked. I was told by the agent that the flat was unfurnished but came with white goods - the property ad mentions specifically a washing machine.

After paying the holding deposit, I was informed that the flat doesn’t actually come with this included, and I was misinformed on the advert and by the agents. I haven’t signed anything, and the agents have said they’ll return my deposit to me in full if I don’t want to continue. Are they required to furnish the flat in line with the advert? Or given that I haven’t signed a tenancy agreement to that effect, are they free of responsibility?