The maximum frame measures about 198cm/78" wide, 140cm/55" deep and 158cm/62" high. The seat back is 160cm/63" wide by 81cm/32" high and the seat is the same width and 60cm/24" deep. The frame can be unbolted in several places to make it easier to transport. The longest timber is 172cm/67.5". The seat can also be unbolted but it might go into a larger van as it is.
Overall the condition is not bad after many years of use. It's had a coat of protector every year. However, the back two legs have rotted a bit as shown. They could be spliced or maybe you'd get away with reducing the height but the front legs are ok. There's no canopy or cover or cushion to go with it.
I don't want to dismantle it until I'm sure it will be collected. It might be easier if we did it together then you'll have a better idea of how to reassemble. I'm open to discussion. It should be in a family home with kids and with a little tlc it could last several more years.

Outdoor wooden two seater garden swing seat (Horwich BL6)