Hey team - it's done. I want to say a huge thank you to everyone for the help. Having faith certainly helped a lot CPalacay... OK, so here are some details for those that follow. I reckon it took me about an hour, this includes getting up and down and trying different approaches at the four various stages. Having researched and read about the process there were several salient tips that really helped.
step 1: As suggested, moving the O2 sensor wire by pulling on the metal clip helped significantly, I also bent the metal bracket on which the clip is situated out of the way, this was a huge help in terms of getting my fingers and other tools up to the sleeve (see next image). To Undo the wiring harness I used an 8" pry bar to rotate the wiring harness outer collar from the 5pm to 1pm position (see second image), this was pretty easy and the wiring plug disconnected easily. Note that I used a paint pen to mark the 5pm position on the transmission, I did this to help with reassembly.
step 2: The next step was to remove the valve body sleeve, you first have to release the white tab within the transmission, see respective YouTube videos for more details on this; my tab came down fairly easily. I used a combination of screwdrivers and pry bars to leverage the sleeve out, I also used the white paint pen to mark the bottom of the existing valve sleeve so I had an orientation reference. This step took me a while as I tried with different tools but it eventually moved and came out (with a shorter screwdriver), once out I moved maneuvered it above the pipes and it came out relatively easily.
step 3: I would say this was the most difficult/scary step, I used the paint pen to mark the new valve sleeve (6pm position in the following image), in the image you see the old (right) and new (left) sleeves; in particular I'm interested in the flange on the inside of the sleeve as this flange has to be lined up with the groove on mechatronic unit (off course you can't see any of this). I applied silicon grease to the o'rings. Once the sleeve was in position and facing the right direction I used the ink mark to rotate the sleeve to about 6pm and could feel a very slight engagement of the flange with the mechatronic groove; this is the most scary part as you're not totally convinced! One other point; the paint mark is also on the cylindrical part of the sleeve as you can't see this top edge as depicted by the photo. Once the sleeve is in place I had lots of fun trying to get it installed, in the end I used a longer pry bar (see image) and used the cross-member to create leverage; it eventually slid in to the transmission! Phew! This took me a good 20 minutes of fiddling around. I then re-engaged the the white tab as mentioned in step (2). It engaged easily.
step 4: Plug the wiring harness back in... Again this took a little fiddling and to get decent access I had to really get under the vehicle to get my hands in a good position. I mostly did this by feel and eventually felt the locking ring engage (lets hope it works when I start the vehicle...)
That's it, I hope this helps others! Once again, thank you everyone for giving me the confidence to tackle this.