Thank you everyone for your empathetic and kind responses. Sometimes it's so helpful to tell someone who knows.
So it was a horrible afternoon. We were very low key when we arrived, only telling the previous owners that we'd take a look around the garden while they 'finished up'. (Could see then that it would take much longer than their estimate of 1pm) Even then the seller could have saved it by being apologetic but he responded to my statement (we will be looking around the garden) as though we'd asked permission. We owned the property by then so not asking. No apology.
I waited until 12.50pm (contract said 1pm) and then went into the front yard. I asked the removals if they thought they'd have enough space for everything I could still see needed loading and one of them snarkily said 'yes madam we are professionals' so I said 'and in the next 7 minutes?' Because clearly that wasn't true. And he kicked off immediately - rude, abusive, swearing, homophobic (my sister was with me and he kept saying you and your little husband need to fuck off). I went into the house and told the previous owner that hie needed to stop his removals abusing us and get out. Could we just be reasonable? No, I said, I bet he wished he'd been reasonable when we'd asked for eg a carpet fitting measurement. It was now my house and not his. Now I see that he didn't want anyone to see the state of the place...he tried the argument that the longer we wasted time arguing the longer it would take them and I pointed out that I was paying our (competent, productive) removals to do nothing whilst his (inept but cheap) removals pissed about smoking. He then spent another hour putting individual items in his car whilst pretending to be on the phone so he didn't need to talk to us. We went to have a look around and found the most disgusting house I've ever seen - seriously.
Our cleaner arrived and I've never been so pleased to see anyone. She removed a basket of dirty laundry from the utility room to his car (!) and then we decided to start cleaning even though he hadn't left yet. She and I picked up 2 black bags of rubbish including an apple core that had mummified and a toast crust that had seen a different season. The living room was covered in a thick layer of detritus, food, dust and black filth. Unflushed toilets. Food still in the fridge and freezer. Blood on the walls. Unspeakable things.
The carpets are so bad that we have a carpet shampoo booked for tomorrow even though they are being replaced in a week (another long story about how our sellers couldn't compete last Friday thus allowing us to replace carpets on Monday because they absolutely had to have these amazing removal company- your know the ones who weren't out on time, moved really slowly and abused us when we turned up.) and my 66 yo mother literally scrubbed the utility room for an hour before we could put anything into it. Also power sockets broken and hanging off (and a whole room not working) mould and limescale everywhere, broken toilet seat, chipped sink, locks that don't work. All the bins overflowing, fixture and fittings included in the sale removed... I could go on for ages.
By the time I read your lovely responses and we'd made a dent in the cleaning we were beginning to remember why we'd fallen in love with the attached 1.5 acre on which we plan to build, but given we need to live in this house for the at least 18m it takes, it was hard to manage. I sincerely hope none of you have anywhere near the same experience.