Getting the Effing speed transducer off my TD5 110

Re Posted from a different forum on this site....
Hi, my inspection pit is still a month away as my mini digger is awaiting a new track.... till then I've ordered a new OEM YBE100530 transducer from ebay for my 06 TD5 110 as both speed and milometer have never worked in 4 months. Looking at the spare thats arrived its a cheap plastic free spinning 22mm nut fitting although the 3-pin electrical connector fits. The original part looks like its a 10mm nut holding a flange of some sort but is a bitch to get to without removing the handbrake disc assy and or prop shaft etc...... anyone got a quick method for removal of this simple sensor? And do I even have the right part? The P/N matches but there's no hex nut on the original from what I can see lying flat on my back with dust in both eyes!

When there's nothing else in the way, I can get a 1/4" socket of the relevant size on an extension bar down the gap between transfer box and brake backplate to get mine out. Now I have an overdrive, I have to take the handbrake off. If it's just for small jobs like this, I don't take the handbrake apart, I just undo the four bolts that hold the backplate to the transfer box and let it dangle on its cable. No messing about with springs and cable nipples that don't want to fit in their holes!