I would highly advise to steer clear of Yopa.
My property was marketed and shortly afterwards, an offer was made for the full asking price. The agent misled the buyers about the construction (but denied this). After 3 months of wasted time, the buyers pulled out (due to the construction/mis-information given) and what followed was several no-shows for viewings from the agent who eventually admitted these being down to personal issues.
10 months later, the house had not sold and the fee was due. I raised a complaint with Yopa and subsequently with the Property Ombudsman.
Dealing with the Yopa complaints team was like dealing with robots. The complaints process was far from easy and they tried to "play down" the issues I had experienced.
I have bought and sold properties over the years, and this has been the worst experience ever, causing a great deal of stress.
Avoid at all costs.