I only had 1 camp active. But when I fried to fast travel to it, it said it was blocked by another player. I scrapped and rebuilt both camoss now, lots of trouble getting PA display ls back, but got there in the end.

Did you activate the camp that is not appearing, even on private worlds you can only have one camp active at a time.

One camp appears on map but doesn't exist when I go to the location. The other won't activate and each say they are blocked by another players camp, even though I'm on my own.

I can't place any camp in a private adventure. Though they appear on the map.