It’s pretty straight forward (from me, Peter - it works for me!);
You buy the land from Gladwish Land Sales.
Then add the recommended percentage.
Now let G.L.S. advertise it until it is sold.
or
Add as much you want to make and advertise it with FELA, GLS's sister company.
The other option is long term; keep the land and wait for either the price to go up naturally due to demand in the area. There is the option of applying for change of use, or planning permission for a stable of even a house.
At most sites there are ‘Plot Owners Association’. Some of these could group together and make a joint application for planning permission. The options are broad and anything is possible, but nothing is guaranteed.
Whatever your plans or dreams, you will still be the legal owner of a piece of true Freehold Land, with your name on the title deeds issued by H.M. Land Registry.