In big developments land owners or potential landowners apply for outline planning permission, get it, then sell to a builder to actually do the work.
It's more complicated than that. The big problem for larger schemes is the considerable up-front costs of applying for, then obtaining planning permission, and that there's no guarantee that a permission will be granted. If the landowner is (very) wealthy, they might do it themselves. Often landowners will get no further than promoting their land for designation in the Local Plan for the area as a site to be designated for development, and then seek some kind of agreement with a developer under which the developer agrees to fund and pursue the planning application itself, and either agrees to buy the land conditional upon obtaining the permission within an agreed time limit, or is given the option to buy at something of a discount to reflect the fact that they have put in investment at risk in pursuing a planning application. Quite often the developer will take its agreement at the stage that sites are being selected in the Local Plan, as this process can be protracted and expensive as the plan has to be examined by a planning inspector, for example if the plan is subject to challenge through the courts, or if there are competing sites being put forward and the authority or inspector has to choose between them.
In the last couple of decades a new type of player in the market has emerged. These are land promoters. They use risk capital to promote sites through the local plan and planning application process, and if the whole process is successful, the site is sold and they get a share of the sale price as their reward. This has provided a supply of sites available to build, without the actual builder/developer having to tie up risk capital in promoting the land through these processes with no guarantee of success. The large national housebuilders have different overall business strategies as to how much they invest in what is known as strategic land, and how much they prefer instead to buy (to use the industry term) "oven-ready" sites.
If you are a promoter or well advised landowner going the whole hog and getting a planning permission, you would be well advised to get an outline permission and sell with the benefit of this. Each developer has its own idea of what will sell, its corporate style image and (in most cases) standard house-types that it will want to use, so in most greenfield sites it is a waste of money to approval of the details before a sale. There's a little risk left though at the outline planning stage, as it can take a long time to get those reserved matters approvals needed to start on site.
If outline planning permission with reserved matters 3 years. If you then submit detailed planning permission (reserved matters in the outline) then another 2 years. If you apply for permission with all the details then 3 years.
Correct - this was shortened from 5 years by the Blair regime, just in time for the 2008 crash, which meant that there were a number of sites with no buyers, or buyers with no cash to implement with time running against them. However, all you need do in that time is implement the permission - take some initial step such as cutting some foundations, to keep the permission alive
if you have cleared off all the pre-start conditions and obtained the reserved matters approvals.
But if you have invested all that resource in obtaining the planning and approvals and buying the land, that money is burning a hole in your pocket, so you have every commercial incentive to build and sell at a price and rate the market will bear to get your money back. Closing a site for a volume housebuilder is very much a last resort, not least because re-opening it incurs further expense.
The Paignton scheme is interesting. I see it's a mixed scheme of retail, industrial and warehousing that was granted outline permission in 2016 pursuant to a 2014 application on a major redundant office site. From the planning history it looks like quite a bit of the other elements have been built. The permission seems to have been obtained by a not very substantial company. The residential elements are still up for sale as far as I can see. I assume that approval of reserved matters for a full (in theory) ready-to-build scheme has been obtained to keep the permission alive for the residential part of the scheme. There must be something that has put off the any housebuilding company from buying - it could be any one of a number of things - the party promoting the scheme may have designed something that no-one can make work financially in the local market, the presence of an adjoining busy retail/commercial site might hit sales values, or their due diligence has disclosed technical problems that has scared off buyers.
As the permission in the 2016 permission has been implemented, it is still a live permission, but it's an unusual animal to still be there unbuilt. This is not a housebuilder sitting on a site, it's a landowner, promoter or commercial developer who cannot sell it for development. They might (of course) have already got the money they have spent buying and promoting the site back by building or selling the other elements.