At approx 7000sq ft, that's £1710 per sq ft. Wow! That's comparable to SW Central London. SE1 prices are going to zoom up and up as development gathers pace - Elephant and Castle, Waterloo, Bermondsey and London Bridge. The Shard is expected to market at around £4000 per sq ft for the upper floors (of course there's that premium for views over to the English Channel).
Unfortunately not. One of the more contentious aspects of council tax is that it doesn't, at the top end, reflect the value of the property.
So, when you move into your twelve million pound flat, you'll pay the same 2,443.92GBP as someone in a flat that was only deemed to be worth 320,000GBP in 1991. That's only twice what someone in an 'average' Band D property pays.