what is this ?

[G3WRT]

I have now done 650 miles in my 6.1 coast. My first serious trip and I stopped in Kings Lynn lovely spot. This was after 100 mile drive no stops. I parked in a slightly rocky place!

After coming back from a walk I noticed this on the floor outside the rear!
How did it get there and where from? most importantly why?

 

[G3WRT]

I have now done 650 miles in my 6.1 coast. My first serious trip and I stopped in Kings Lynn lovely spot. This was after 100 mile drive no stops. I parked in a slightly rocky place!

After coming back from a walk I noticed this on the floor outside the rear!
How did it get there and where from? most importantly why?

View attachment 98175

and BTW the rubber ring is very loose on its fitting - I would say oversized?

 

[CannellWalker]

Not sure of the scale but it looks like the lid to the gas storage in the water tank.

 

[Saesneg Shaun]

Not sure of the scale but it looks like the lid to the gas storage in the water tank.

Agreed it does look like that lid. Was the van still locked on your return and is your campingaz bottle still present?

 

[Ocean Spirit]

...another vote for the gas compartment lid.
Slim chance but I'm just hoping someone thought you might like a spare.