In London dozy peds are pretty commonplace. Of course I negotiate with care but sometimes the ones that go to step out suddenly or move to attempt a run across benefit from a quick 'NO!'. Best for everyone :-)
Approaching busy ped crossings, especially those on a bend it's often worth a couple of friendly tings on the bell to let peds know you're there. Can be easy to miss seeing a cyclist. A classic is the turn off Aldwych heading up Kingsway- it's quite a sharp corner with a crossing right on it!
Often I'll complement a 'NO' or bell with a 'Sorry, thanks'. Very British.