It wasn't overly difficult, it was just the access that was a bit trickier than the front, the tools I had weren't absolutely perfect for the job but I managed anyway, there's always a way to make do, even if , as a last resort, you have to go and buy some tools, it's still cheaper than going to a garage.
I found it easier to use a socket bar (with a 'knuckle' joint on it) as it lets you turn the plugs with the handle of the bar at any angle you like, my ratchet is fixed at 90 degrees, so was harder to get in between the top of the engine and the bulkhead (the panel behind it), longer handle on the bar also gives you more leverage than shorter handle on most ratchets if they are a bit seized in.
Good luck.