If you buy new you will lose serious money overnight. Keep in mind.....the site owner has absolute control over your van e.g. if he decides he wants to move your van from the lake view to a view of the pigsty he can do it. If you buy used he can decide to guaranty maybe just 5 years before forcing you to buy a new one or go.....with nothing.
And......if (big if) you are allowed to sell it privately....he will take a minimum of 10%.
You could have many many happy years there.... but there are many potential problems.
After spending best part of £40K on my static I concluded I would have more consumer rights buying a four hundred quid washing machine from Currys.
As a static owner, you are completely at the whim of the site owner - if your face fits, fine, but there's only one winner if you lock horns and the site management takes against you.
More by luck than judgment, it has worked out OK for me.
Site maintenance has not been to the standard I expected, but the owner has largely left me alone to get on with it.
The site I'm on is privately owned, which is good and bad.
No big company rules to abide by, but there's no rules to rely on if there is a dispute.
My static is approaching 10 years old, there are no published age rules for the site and there are still statics there which are older than mine, so it looks like I shouldn't have any worries for a few years.
I have what might be termed a premium pitch beside a river.
The first sign of bother will probably be if I'm shunted off that and plonked somewhere less desirable.