There are more happy static owners than there are unhappy ones, but unhappy ones are more likely to publicise the fact on social media, hence the horror stories.
Some of the stories are because people did not carry out any research, or even read their contract, before buying and then discovered that they did not like the terms and conditions they had signed up for - so it is pretty much a self-inflicted problem; rather like people who move to somewhere in the middle of a rural farming area, and then start complaining about normal rural farm operations going on nearby.
There are indeed some rogue operators out there, but there are in any business, and in most cases they are easy to avoid.
Remember that all parks are businesses, they are in it to make a profit and you will be the one providing that profit - many of the complaints seem to come from people who apparently think that the park should be a charitable organisation operating on very slim margins..
You can check any park that is a Ltd. company on Companies House website (free) and be wary of any company whose directors seem to be linked with a lot of dissolved companies. Google the director's name and see what comes up.
A company that has been trading under the same name for several years is a better bet than one that was set up 3 months ago - but bear in mind that some operators create a new company for each park they own in order to make sure that records and finances are kept correctly for each park, and is not at all anything to be suspicious about.
Some small parks may not be registered companies, so not shown on Companies House, still google the owner though and see what comes up. No news is usually good news.
A good company will want you to be satisfied with your purchase, so will be happy to answer questions and provide a draft example of their contract for you to see. They should also have their site licence on display, and be upfront about payments for pitch fees, utilities, etc.
Other van owners will be your best guide - talk to as many as possible (now things are opening up this should be easier than it was) to find out what it is like.
If the park is one of the "oh, we don't bother with contracts, we trust each other" - remember that no contract = no proof of what your terms and conditions are. The only legal protection you have with a static holiday van is the consumer rights act (for the van itself) and the law of contract (for the use of the pitch) so a contract that you understand and are satisfied with is very, very important.
If the salesman seems evasive, or brushes off questions - that is a warning red flag.
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