I would also go with getting someone in to do it,
They will know their machine
Have a more powerful machine than you could get
Charge you for the hours worked, not the days of hire for the machine.
You can watch and learn so that if you hire a machine in the future you will
A/ have a good idea of how best to use it
B/ you will be working on ground that is easier.

A few years ago my Howard gem was out of action and I had to hire a machine
from local hire shop.
The job took me almost 3 days with their machine rather than about 6 hours
with my Gem.
Felt like digging the ground with a tea spoon instead of a spade.

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk