Seeing as your time horizon is so short (one year at a time) and the fact that your looking for something low risk and which you may need access to your funds at short notice I recommend putting your money into a deposit account. Check out the best buys forum for a list of the best deposit rates for large lump sums.
If on the other hand, you are willing to commit a certain amount of money for at least five years you could consider a mix of index tracker funds with Quinn Life. As with all investments you should consider seeking independent, financial advice from a qualified financial advisor before making any decision.