Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Gains on the sale of residential property are subject to CGT at 20% or 28% or a combination of the two rates depending on the level of your income in the tax year of disposal. Gaims made on the the disposal of any other assets which do not qualify for entrepreneurs' relief are subject to CGT at 10% or 20% or a combination of the two rates depending on the level of your income in the tax year of disposal. Take a look here for information on the new CGT rates.
You are selling land so the residential property rates won't apply to you, notwithstanding the fact that you will be paid from the proceeds of house sales. That's assuming that the sale agreement doesn't entitle you to a share of any profits above a certain level in which case you could be treaated as taking part in a property development and charged to income tax and national insurance contributions instead.
I hope this helps b ut let me know if you have any further questions.
I think that you are correct. You are just being paid for the plots piecemeal because the buyer has to generate a sale in order to pay you so you will pay CGT.