I've just been through getting all sorts of quotes after the change from M&S.
After declaring my bikes they want £650
American Express (recommended on here) had similar cover for £380
It's a bit more hassle because you have to declare lots and lots of things, but that's a pretty big saving.
Only problem is M&S used to do 0% finance, whereas AMEX is some silly 30% or something so the monthly amounts are only about £10 cheaper. Tempted to try and pay it one chunk.
Most of the other recommendations (AA NFU) had limits that prevented me being able to use them. £3000 total outbuildings for AA for e.g.
One thing that I didn't know:
They all seemed to think that a bike visible inside a locked car wouldn't be covered, in the same way an iPhone left on the dashboard wouldn't be covered. I'll have to start locking the bikes to some immovable part of the car inside for them to be covered.