Don't invest your money with AON!!!
My experience is that their fees are extortionate. Unlike many other providers I couldn't get an up to date online valuation of my pension fund with them without asking for one. Once I got the valuation I decided to move my fund to another provider. When I requested the transfer they then insisted on charging me £300 for this because it meant I was asking for another valuation within a year.
I believe £300 was disproportionate to the amount of effort required but when I made a complaint they insisted they were entitled to charge that amount.