colo60

I almost always stay in laybys, carparks, side of the road etc.
Dispite what some will say, its fine and isnt illegal in any way.
In a car park, if it says something like 'no parking between 8pm and 8am'.
That is legally enforcable.
However if a sign says something like 'no overnight sleeping' it is not enforcable because there is no legal definition of 'overnight'.
The signs must say what vehicles and state a times between that they are not allowed to park.
But I tend to stick to the rule of, if there is any sign trying to stop it, I dont stay. Even if I know its not a legal sign because Im not out to annoy anyone.

As for in the side if the road or a layby.
Providing you dont get tables and chairs out etc, you are parking and not camping, so anywhere you can legally park, you can sleep.
We tend to pull up late, close the curtains and just go to sleep.
I often park in industrial estates but make sure you stay on the public road bit and are prepared to move off when people start showing up for work.

Many places I use often have the police drive by at some point, they have a look, prob do a PNC check on the motorhome to check its insured etc, they never disturb us and often wave or smile back to me.

I only stay in one place for one night, so I dont bother any one and I am always happy to move on if asked, with this attitude we havent had a problem ever in 36 years of doing it.
Its great to have the freedom to go where and when you want with no planning, which for me is the point of a motorhome.

As for Orpington. I dont know it sorry.
Canterbury park and ride overnight area is nice and was £3.50 a night last time we used it.