I was at a BSAP meeting where the 1 Tower Bridge developers gave a very heavy hint that the supermarket there would be Waitrose, but the development will not be complete until 2017 ...I suppose the supermarket could open sooner as it is in the section currently being built on the corner by the old school (to be a boutique hotel)
Just going to throw my 10 cents in. It seems rather crazy/odd to put a Waitrose in 1 Tower Bridge with one already right across the river and cannibalize it's own business. The Shard would have made more sense and capture the London Bridge commuter market.
The petrol station rumor - was due to Waitrose / Shell doing a deal for mini shops in the garages which they were testing in a few sites - not sure if that is still going ahead but planning was put in for the redevelopment of the petrol garage.
Another mention of Waitrose's plans for small central London stores in the Evening Standard yesterday. They're opening one at Monument and 8 more which they won't disclose (which possibly explains previous denial), would guess there is a fairly good chance of one of them being in the London Bridge area.
I went to the Kings College planning presentation yesterday for the part of Borough High St. they own .. seemed alright and they spoke about possibility of having a Waitrose as their resident supermarket ..
One of the locations is Victoria Street SW1; not sure why they're "tight lipped" on that as it's mentioned in a City of Westminster development update newsletter and the planning application is available online.