@alyx @kwf If I had to guess: these boxes come in standard sizes. This particular one is rural and supplies only a handful of customers, so it has plenty of spare rack space. Unlike racks in data centres or exchanges, where space is always in short supply.
Edit: it’s probably also on the route to work (or minor detour) for a staff member at the ISP. In fact it might be the box supplying the staffer’s own home internet connection.
@pmdj @alyx @kwf I'd also add.. who wants to drive hours into central London to the datacenter !