A limited nuclear attack on the UK - how much damage could it do?

Some of the detonations

 Out of curiosity, I have decided to model using NUKEMAP a 'limited' nuclear strike on my home country, aiming at key military facilities (air and naval) and avoiding cities just for the sake of it, but I will hit Central London for command and control purposes.

For ease of calculation, I will be limiting this to Topol/SS-25 ICBMs at 800kt each, going off 1000 metres above their targets - this does more damage, but produces less fallout. This will just cover the initial attack - not fallout, which is very much weather dependent.

The targets are: 

Aldermaston (nuclear bomb construction)

RAF Boulmer (Air Defence control)
RAF Brize Norton
RAF Coningsby

Faslane (Naval base)
RAF Fylingdales (Early warning radar)
RAF Lakenheath (USAF)

London (10 Downing Street to be precise)
RAF Lossiemouth
RAF Marham
RAF Menwith Hill (US/UK intelligence and communications facility) 
Plymouth (Naval base)
Porton Down (Chemical Weapons)
Portsmouth (Naval base)
RAF Waddington


That is 15 ICBMs... Unfortunately, the system keeps resetting itself, but I end up with well over a million dead, mostly those in London, Plymouth and Portsmouth, but other areas will produce thousands of dead. I did not cover army bases, but it is entirely possible that the Russians could eliminate the UK militarily with 30 or so ICBMs.

However, the UK would still have a missile boat out in the North Atlantic with 8 Trident missiles and those could do a lot of damage in return... not to mention all the US boats.