If you are looking to invest more than your ISA allowance, then you may wish to consider a General Investment Account (GIA) alongside a stocks and shares ISA.
Your GIA offers you access to the same portfolios as a stocks and shares ISA, and there is no limit to how much you can invest on an annual basis. However, unlike an ISA, interest you receive from your investments is taxable; the exact amount of tax you pay is dependent on your circumstances.