Broad Fork

Spot on agapanthus.
Have the handles leaning away from you so as the tines are upright, then stick your boot on the crossbar and stick the tines into your soil, then the curved shape of the tines means when you pull back on the handles, the soil comes up in a rolling motion, rather than lifting a great heavy clod and causing more back damage than I have got already.
According to the Eliot Coleman book, you can prepare a lot of ground in no time at all. I think it will be fine if your ground is worked already, but not sure on a plot that has not been cultivated for a while.
Thank you all for the comments and questions. I do like this forum.
Regards Huzey.
P.S. Might have come up with another idea involving a rotovator and some other bits of steel. All will be revealed in the near future. Guess who likes welding!  

Thanks trillium.
That is very helpfull. I manged to blag some 10mm bar today to make a few extra tines, so watch this space.
Once again, thanks very much.
All the best
Huzey.