I'll give a perspective as a would-be buyer, not a would-be seller.
2nd hand vans on this site often strike me as ambitiously priced, to put it diplomatically. E.g. If I can buy a new Ocean, from a dealer, with a bunch of extras for just under £70k (which I currently can), would I really want a 2 year old Ocean with fewer extras, from a private seller, for £64k? I just don't see the appeal of that and wonder who does. Without calling out specific ads, prices also do not seem competitive relative to used pricing from reputable dealers, which I think most people would prefer (ease of financing, someone to go to if problems arise, you can order online and then book your train and drive the van home with everything taken care of, or even have the van delivered, etc.).
The thing is, I am not sure to what degree asking prices from private sellers are set with a bit of negotiation room in mind. If a person with a 2 year old Ocean would accept, say, 61k or 62k, then maybe I'm interested. But I'm not going to drive around the country looking at vehicles by private sellers to find out, when I can click a couple of buttons and buy a nicely specced, new Ocean for <£70k, or a 2023 Ocean from a dealer for 63k (a couple on auto trader for that). The exception would be if there were something distinct about it that I liked, e.g., a colour (Starlight Blue please!).
That all said, I know how annoying it can be as a private seller to list a vehicle at the actual price you want, indicating 'firm', because people will still show up and lowball you. A few years ago I sold a Honda Jazz. I was extremely busy with work and with a newborn baby so I listed it on auto trader for 5% less than the next cheapest same year/same spec Honda Jazz in the entire UK, and explained in the ad how I set the price and why. I still had endless inquiries from people offering me 25% less.