Some things you should know before buying land plots:
There is no documented case of any plot sold by a land banking company ever receiving planning permission.
The prevailing opinion among developers and builders is that they would not buy a site comprising many plots with many owners, particularly where many of those owners are foreign nationals, resident overseas. It is logistically too complex an undertaking.
Most land investment, like many similar forms of investment, is unregulated in this country. There's no independent oversight of standards. However some land banking companies have been closed down by the Financial Services Authority or other regulatory bodies because they were found to have been operating illegal collective investment schemes.
As a result, most land bankers now explicitly state in their literature that they do not operate collective investment. These statements have yet to be tested legally and are probably open to challenge as the selling tactics of the land banking companies have not changed.
Many land bankers have operated investment schemes before without conspicuous success for any of their investors. These have involved things like ostrich farming and vintage port to name but two. Some people have been prosecuted as a result of these earlier schemes and barred from being company directors.
The non-refundable deposit you may be asked to pay could be more than the value of the plot in its current condition
If you pay such a deposit on any rural plot, you have no right to a refund. While certain types of transaction are now protected by a statutory 28 day cooling off period, transactions involving sale of land are explicitly excluded from these provisions (distance selling regulations).
It is official government policy to give priority to re-using previously-developed land within urban areas, bringing empty homes back into use and converting existing buildings, in preference to the development of greenfield sites (ref Planning Policy Statement 3: Housing). While it is clear that some green belt land will have to be released in the future to cater for increased housing demand, there is simply no guarantee that your plot will fall into this category.
Planning permission is in any case highly unlikely to be granted piecemeal, to individual plots and applications will need to be coordinated for all plots within any one location. What guarantee do you have that the company which sold you the plot will still be there in 15-20 years' time to coordinate a planning application for a whole site comprising many plots the owners of at least some of which may not even be traceable?
As a land owner, you have certain duties to maintain it. Under existing legislation, local authorities can take steps to have land which has become neglected restored. According to guidance issued by the Office of the Deputy Prime Minister in April 2004, these steps could in some circumstances include compulsory purchase of the land.
If you are unable to maintain your plot, you may lose it!