I need a place to park a fair amount of money for up to a year. What would be the best (and most tax efficient) option to do this? I'm taxed at marginal rate, so straight interest-bearing instruments wouldn't be suitable.
Safest will be to use a fixed deposit account at an institution that will give you the highest return.
Depending on your age there is also a tax exemption on earnings for local interest.
If you want something safe then its going to be a straight interest bearing investment. If you want something that is tax effecient then you going to have to look at something that will give you capital growth. You can't have your cake and eat it too.