No doubt it's the climb.

The top floor is several flights up, for one thing. And there's those breathtaking views, of course. And all that sunshine pouring in through the vast picture windows which line the gables. Not forgetting the fact that air at altitude is that little bit thinner.

That surely explains it. The breathlessness, that is. It can't, it just can't be the building itself. After all, St Clements is deconsecrated ground.