Lincoln would make an awesome setting! It has the historic beauty, and university ‘affluence’ but also the mid/north deprivation. I would think, being as you are looking at family secrets, and being as the rich, chic family with secrets is a trope probably too predictable… I like the reflection you could build from a very historic setting – history and mystery etc. And that setting could perhaps have the quiet/semi abandoned atmosphere of many historic settings where half the houses are second homes empty most of the year, or perhaps a place buzzing with university students/staff – that balance of tradition and change.
I love the pitch by the way!