Oil ( ?) leak in bathroom ?

After leaving the van for several weeks I found, when I came to clean it, a quantity of clear, odourless, viscous liquid - almost like hand gel- on the floor below the hinge of the swing wall washbasin. It had run into the well in front of the toilet and was quite tacky. I've never seen any of this before and it wasn't anything that had leaked from any bottles of shower gel etc.

We've just been back and there is a little more but not a lot appeared. The hinge seems to swing as smoothly as it ever did.

Any ideas gratefully received !

breakaleg wrote:Possibly the fluid from the stay on the back of the swing wall? Is there any sign of fluid on the rear of the swing wall?
Pete

Can you see my red face ?  I was so intent on checking that I'd not left a bottle of hand gel or similar behind the shower wall that I didn't look up and register the stay so didn't check it.  I wonder what we've done- first time in 6 years- to bring a leak on ? 

Will look next visit and thank you.