Sheffield 3 is the owner absolute.
Companies operate under property law as "legal persons", separate to the owners and directors, can enter into contacts, sue and be sued, etc.
The sole director is Chansiri but it could very well be you or I, the owner is still Sheff 3.
Now companies can get struck off. One way in which they can be stricken off is if there is no director or person with significant control. Currently Sheff 3 has a sole director - DC.
Now I don't reckon it's beyond the realms of possibility here that if DC has committed some dodgy dealings or financial crime, he could be struck off as a director, leaving Sheff 3 without an active director, making Sheff 3 in breach of the Companies Act, which could lead to the company being shut down.
Someone help if you know, RE what happens with directors in that case, as I might be wrong.
But if what i think happens, happens, then if the legal person (Sheffield 3) ceases to exist, the land passes to the Crown Estate/Duchy of Lancaster as bona vacantia, or Vacant Goods, i.e ownerless property.
TL:DR
Chansiri dies or gets struck off as director, possible that ground ownership passes to the Crown estate.