Leaking 12mm pushfit connectors

Our preloved van's water system was perhaps not drained/winterised properly by previous owner. I think most of the hot and cold 12mm pushfit connectors have leaked ( and so been replaced) now we've had the van a year. The latest - will it be the last? - was from one of the 6 connectors under the Thetford toilet which caused water to leak again from the rear of the offside wheel arch.  The connectors under both sinks and to the shower had been replaced earlier this year! 
 The technician at our local dealership ( which is fully booked for many weeks) showed me how I might access the suspected problem area without too much difficulty armed with little more than a screwdriver! So, 6 screws came out followed by  careful removal of the (outside) loo cistern filler and then, the complete loo assembly was gently lifted off its base. This revealed  the  troublesome (6) connectors and tide marks - obviously a leak of some duration.
Hopefully, this winter's preBrexit trip to some sunshine will go more smoothly than last February's.

Following my post of 22 Nov, I found that the feet of the loo's timber pedestal were forcing hot and cold pipes out of their natural line so putting lateral pressure on the pushfit connectors. 
Also, the pipes were mostly too long so they were putting even more flexing pressure on the pushfit joints. No wonder the eventual  leak.  
Now, having reconnected, I have put a "drip" tube through the floor directly underneath the 12 joints, carefully avoiding cabling under the van. The floor had been dried and there is now a circle of silicone on the floor around the joints to prevent any further possible leaks spreading water far and wide.
The system will be fully checked for leaks before replacing the loo.

Congratulations for remedying the leaking problem with your van.