IMHO Motorway work best for newer cars with all defects notified. I’ve sold 4 through them. The last 3 valuations were reasonable and just after Covid got a lot more, way over the PCP balloon payment.
Recently sold my M40i. A year ago it was coming out at £33K. In July it came out at £36,790. It sold for £36,120 which was much more than I expected. My stealer offered £30K. This for a Misano blue with all packs except the black shadow line. Just serviced. 70 on a private plate with 10,500 miles. It had the OEM wind break and the glass Windschott, plus track pack PPF. There were a few bodywork marks and some small kerbing. No hassle or quibbling from the purchasing dealer. They added approx another £3K IIRC and it sold within 2 weeks. I’d done less than 1,000 miles in the last year. Great car, looked and went well.