This whole kitchen renovation is making me crease, her thought process behind it is completely transparent.
Hinch had that extension built, but realised she couldn't change the kitchen right away because the Hinchers relate to it being smaller/ordinary/more attainable in size/finish, plus it's pretty much the money maker where it all started for her.
So she "tweaks" it with new worktops, a few more cupboards and a failed kitchen island. Hopefully the Hinchers won't think too much of it.
Hinch waits. She's still not happy with her kitchen.
Pretends "the wall" is something she has randomly started thinking about knocking down. Makes her Hinchers believe they are part of the decision by polling and letting them have their say.
Books a holiday, pretends that the work is going to be rushed/fitted in during the time they are away.
Arrives home to a new kitchen/diner and island, which is what she really wanted in the first place when the extension was built.
She meticulously planned this well in advance, plain as day.