its what I used to do when I had a few bikes all at the same time, a little research may get you a decent discount 2 bikes insured on one policy & another bike on a stand along policy can be cheaper than all 3 together & it sometimes works better to use different companies for different bikes
Remember companies on compare the market offer discounts if you are a new customer because they want the trade & the quote on there will often be less than the renewal from the same company because of this, it hacks them off no end if you take their net offer & when they ask for your proof of no claims you tell them to look at your last policy which was with them