In a comment webofevil says:
Lord Falconer has just announced in the chamber that senior coalitioners have said privately that they're willing to decouple the two parts of the bill so that the 5 May referendum deadline doesn't mean the boundary changes are skimped and botched.
If so that would be a very interesting development. To my mind an AV referendum is a defensible piece of legislation, though I will vote 'No'. A gerrymander of constituencies to benefit a single party is indefensible.