Refers to the land and buildings of a residence, especially a large or official one. Often used in news reports or formal descriptions.
警察が邸内を捜索した。
The police searched the premises.
A burglar broke into the grounds of the residence.
邸内には美しい庭園がある。
There is a beautiful garden on the grounds.
邸内で火事が起きた。
A fire broke out on the grounds of the estate.
The host gave us a tour of the grounds.
構内 refers to the premises of an institution such as a school, factory, or station, whereas 邸内 is limited to the grounds of a private or official residence.
邸宅 means the mansion or residence building itself, while 邸内 means the grounds or premises surrounding it, and the two are easily confused because they share the kanji 邸.
Compound of 邸 (residence) and 内 (inside). The reading ていない is the standard on'yomi combination.