I contacted a cleaning company to arrange a weekly house clean. I gave a detailed breakdown of each room and what I wanted in each room and was told it would take around 3 hours at a cost of £20 per hour but they couldn’t say for sure the length of time it would take the first time. It actually took 4.5 hours and that was with me telling them not to bother steam the living room and hallway floors and not to bother hoovering the playroom (which were on the original list) because they’d been here so long. There were also things on the list that I realised weren’t done after they left - e.g. I specifically asked them to hoover under the sofa, beds and other furniture which wasn’t done. The person I spoke to who gave the quote / estimated time wasn’t the cleaner who came.
As a result of it taking so long I was charged £30 more than expected for less cleaning. They did explain they couldn’t say the exact time before seeing the house, however given I’d provided such a specific / detailed breakdown I don’t think it’s reasonable for the estimated time to be so wrong (half an hour or so out would be fine) and if they’d realised it was way out when they arrived at the house it should have been discussed again when they arrived to agree how long it would take and see if I still wanted everything done or what could reasonably be done within around 3 hours.