There were three models of P1800, the P1800S, P1800E, and P1800ES. The ES is largely what the C30 is styled with similar design queues. It was a shooting brake, hatchback, model with the large distinctive rear glass hatch.
Then there was the early P1800 which was built/styled by Jensen and I don't remember if it was enough of a difference to be it's own model. They are akin to the sandcast models and are pretty rare.
A lot of P1800 owners were snobby and treated their cars like jewelry and I didn't like associating with them if they were like that... The VSA, Volvo Sport America club was full of owners like that and I steered clear of their meets and owners usually. The VCOA ( Volvo Club of America) and Volvo Club of Canada were a lot more fun. I used to trek up to Ilderton, ON when I lived in Ohio to the Canadian Volvo Club annual meet at Fred's Farm. It was a lot of fun and a family friendly event with Volvos of all models represented.
I drove and maintained 240 sedans and wagons (estates) for 26 years and owned a 122S two door which was mildly street rodded and a blast. Loved that car and rebuilt it and worked on just about every part pf that car during my ownership. It was rescued from ending up in a crusher and I should not have bought it, but saved for a better car...but doing that I wouldn't have had the adventures mine provided.
Bikes are far easier to deal with...