Your policy may allow you additional bikes, and often that's a token amount extra on the premium, premium being based on the bike that would be the greatest cost to insure based on risk or value. Think Calmbiker's policy went up by about £20 when he bought the Z750.
Unless you plan to ride both bikes at the same time, then you don't need both insured, just the one you will use, however you're screwed if the uninsured bike gets lifted.
Phone your insurers, just see what they can do. If you invoke another policy, you may not be able to cancel it pro-rata after the 14 day cooling off period.
How did it work before when you had the Virago and the scooter? Two policies or one multi-bike?
Just bear in mind, many insurers have an admin fee of anywhere between £15 and £50 for each amendment to a policy, so it could cost you more in fees than premium.