Old Fat One,
Not much help with RPI currently running at 4.8% though.
Effectively, all you are doing is subordinating the fear of inflationary or shortfall risk. I'm not suggesting that you have to embrace risk to make money, but to focus solely on institutional risk means that effectively, fear of losing money can become a self fulfilling prophecy.
Dependent on liquidity needs, a Higher Rate Tax Payer currently needs to be aiming for returns of at least 5.5 - 6% in order to just stand still.