In British English the contraction, denoting possession, would commonly be:
She's got a black belt in judo. (She has got a …) YES
She's got her own flat in London. (YES)
She has her own flat in London. (YES)
She's her own flat in London (COLLOQUIAL)
Consequently, in British English, the contraction ‘s without got is more likely to stand for
She is a black belt in Judo.
We use the linking verb be to describe a person or thing; e.g., he's a mathematician, she's Spanish, dinner's ready, the trees are particularly old etc.
EDIT 11th August
I don't mind criticism or challenges, seriously I don't, as long as the tone is respectful. Compare the tone between the two commenters below, I much prefer the second.
Some attention has been directed to the last example, “She's her own flat in London", it is AWKWARD but that was by choice. I deliberately composed it that way to illustrate how the contraction she’s could mislead the reader into initially thinking “She is her own flat…”, which is obviously nonsensical. Although the word own emphasises possession, the contracted form is awkward on paper despite being perfectly grammatical. In speech and in everyday writing, she's got avoids this sore point.