Leave it out, Guv'nor.

[barrydidit]

How much of the £11m goes on making the sign rotate?

Think that goes into aforementioned dungeon to be turned by shackled miscreants

[Gentile]

How much of the £11m goes on making the sign rotate?

Cost of making the toblerone sign rotate: £0

Cost of thousands of strategically-placed PCSO's dotted around London and employed to make the city rotate around the sign: £1M per month.

Yes, that might account for it.

[EternalOptimist]

Carter - 'guvner, the man from the water is here to read the meter'
Regan - 'Oi hamza, you slag, we are going to move you to a different cell, the man from the waterboard is here'
--zoooomm
Carter -'hey, where did HE go?'

[stek]

How much of the £11m goes on making the sign rotate?

That's Rowan Atkinson dressed as the Chief Constable turning a lever next to his desk according to Not the Nine O'clock News...