Posted: 16/03/2015 at 17:58
Some good advice above - particularly Gemma's advice about using some coarse organic matter to improve the soil structure. What are you actually planning to do with your garden? Are you just intending to grass it or are you planning borders / patios / veg patch etc? If you are planning any / all of those it might be worth working out just how many square metres you will then need to grass. If you are losing large chunks of the garden to any of the above it might make the purchase of turf more affordable - and turf does make for an instant garden that you will be able to walk on after a couple of weeks
I garden on clay soil which is very heavy, sticky and compacted in places. We used a mini-digger in our garden because we had to have quite a bit of drain work & landscaping done. If it's definitely a mini-digger (ie one small enough to go through a garden gate) and the 'driver' walks it between locations (ie doesn't sit on it to get from a to b - he just sits on it to do the actual digging) then we found it didn't cause too many additional compaction problems.
However, I would not use it in place of a rotovator or garden spade for breaking up the soil. I would use it solely for stripping off the existing turf and digging out really large chunks of rubble.
I would also be very wary of using a rotovator (if you do have clay soil) when the soil is very wet and sticky. We found the rotovator skidded around all over the place, was actually extremely difficult (possibly a bit dangerous) to use and really started to compact the soil - so much so that we abandoned it until things had dried up a bit.
We used a mini-digger to strip the turf and then the rotovator to turn the soil & levelled using spades and rakes. We bought in loose organic matter (half top soil and half farmyard compost) by the truckload and barrowed it round the garden before using the rotovator again to incorporate the organic stuff into the soil.
When I say 'we' I actually mean a couple of burly chaps - it's pretty hard physical work - but I'm a good foreman & make good tea and bacon butties - so it was a team effort