you can buy reverse threaded lock nut removing sockets from Halfords snap on etc
as already said the reverse threaded socket tools are your best bit if all else fails.they sell them in halfords in different sizes , all they do is fit over the nut and as you turn anti-clockwise the thread grips and removes the nut. just use a vice to remove the nut from the tool.
this sounds just the ticket, are they actually called reverse threaded sockets?
I will have a look tomorrow for one
Mat