The "box" is sitting there
They do that quite a lot
My cab was 'ready' as far as I could see for months, no work being done , no Openreach vans etc
Suddenly very early one morning (approx 4:30am) I tried Plusnets 'Check your Number' page and I was told it was available.
I signed up straight away
Within 2 days it was officially again 'Not available yet'
It was installed on the day I had been told, so was very happy.
As I said it is only gone when the Openreach site says it is 'not available' and 'never will be available'.
Things change just the timescales are often unfathomable
Wait for what happens next but 'Don't hold you breath !!!'