There are lots of confusing terms used in the wine world and the term “Estate” is one of those.
Generally, when you see the word “Estate” on a wine label it means that the winery oversees all of the farming of the grapes. The winery may or may not own the land, but the farming is done by them.
But, “Estate bottled” wines must be produced from grapes that are farmed, fermented, aged and bottled on the winery’s property - they do everything associated with the wine in the bottle. That provides the winery with complete control of their final product.
So, keep an eye out for “Estate Bottled” wines. They are a bit more special. Cheers!