I reckon Lee was talking about an agricultural land plot and Sheen about regulated and unregulated land probably with a property located upon it.
When buying the latter it is more difficult not to get the piece of land that comes with the property as it is written just how much regulated and unregulated land that you are buying as well as showing the plan on the so called SKITSA. However, if you have a fairly straight plot it shouldn't be that difficult to follow, but if like me, you have meandering boundaries that wonder here there and everywhere, only the proper survey team can show you your true boundaries.
The charges raised are PER MARKER POST and are priced at one rate for Regulated Land and another rate for Unregulated Land. If you have a nice square or quadrangular plot then you might only need four posts to mark your territory.
My survey team were the 'officials' but related to one of my builders so, I got the discount plus I got the neighbouring house marked out for free.
However, it seems that my Barn has been built across an old road which is still on the Skitsa with a new parallel road now being pushed further away from my property. Nobody seems to concerned about this and as I have NO immediate neighbours, I am not too worried about it either. When I renovate the barn, I will chop that bit off as it blocks a good view anyway. On my Skitsa, I bought about 3,000 square metres of land, but in fact probably have double that amount which is made up of an added strip here and there and not one piece really big enough to build on. I was wanting to buy the extra but then thought, why, just claim it and if nobody says nothing for the next 10 years simply annex it. Not sure how the legalities work out to be honest.
Anyway, the advice is correct, if in doubt, check as it could be too late after the event and money has changed hands.