Hi, I realise I'm a little late to this conversation, but NEVER use an excavator or tractor on 70% or higher slopes, they WILL roll and decimate everything on the way down. (Including you). I would plant smaller rootstock fruit trees (10-12foot/2-4m) between the gorse and as they grow use the gorse trimmings to mulch them, eventually they will crowd out the gorse and because you haven't removed any roots (just added to them) the soil should stay stable.
Imogen Veneear.
