:smile:
As mentioned in PM's but it may help others, I'd advise to remove the airbox, battery, gearbox mount cage and gearbox cage bracket rather than trying to undo the gearbox mount. The bolt under the ecu and at the side underneath the battery can be a bit fiddly but you'll have all the sockets and extensions in your halfords box.
It will be easier to remove and fit the new gearbox mount once the cage is off as you'll have access to the top and bottom of it for the pin nuts and gearbox mount nylocs. By all means try the otherway but although this way seems long winded, I think it'll be easier for you in the long run.
Not the best pic but you get the idea.

Blurry pic of gearbox cage removed by
Dr-Jekyll, on Flickr
Drivers side is easy peasy but gearbox is time consuming. Make sure you have a jack with some wood under the sump before you start and set yourself a few hours.