In this project I was one of the senior architects of the firm to supervise the construction stage and oversee the follow on tenancy fitouts. It was called the Sun Alliance building at the time and it has been rebadged since.
The basic construction was of load bearing precast concrete panel external walls. The panels were required to be cast to very exacting tolerances to allow a snug fit of the extruded cruciform neoprene strips which were the weather seal between individual panels. Yes, definitely tricky to say the least.
The Clerk of Works, and I spent many hours at the precasters yard carrying out inspections of every panel, and needless to say, there were a lot of them. It is a mode of construction that has nowadays been superseded.