I know its slightly old, but i have just renewed our home insurance without bike cover.
If you make a claim for stolen bikes, you will loose your no-claims bonus, which can be a substantial amount of money.
It cost me £70 less to insure the house this way. That £70 will buy a policy for the bike seperately and not affect the home ins.
One thing - READ the policy and make sure EXACTLY where the bikes are covered. Just because they are covered at home may not mean they are covered 'in transit' or at a sporting event. Insurance companies are not charities they are there to make money and if they can get out of paying they will do so.
if you do claim, expect the next years' premium to jump or even double!
I have 3 bikes all are under home insurance but as (extended contents)