Funny you mention that, I saw this hotel on a morning walkabout and thought what a poor location right on a very busy multi-lane street. I had to take several staircases and footbridges to get back up to St Pauls. It is indeed extremely close to the Millennium Bridge, although it appeared you'd have to walk up to walk over.
On the other hand, I also saw two hotels right next to Blackfriars station that, while also in busy locations, were a short walk to many options.
Also saw a hotel not too far from the Broken called the Leonardo which was well located, as well as the Hilton Curio Lost Property directly across from the cathedral.