A week-ish later, and I have solved my own dilemma.
Here's how I replaced the RHS engine mount, excuse the lack of pics as I didn't really take any during my re-attempt.
**DISCONNECTING BATTERY NEGATIVE TERMINAL IS HIGHLY RECOMMENDED**
**Edited to mention fan shroud**
1) Remove bolts securing the splash tray under the front on the motor and remove the splash tray (if you have one fitted)
2) Jack up car and sit on stands, then loosen the three 17mm nuts securing the lower engine mount bracket to the crossmember, also loosen the 17mm top engine mount nut (this nut may be a different size if it has been replaced in the past)
3) Jack up car, remove stands and lower car back to ground level (This step is optional but recommended if you're not doing this in a fully equipped workshop)
4)Use a Philips head screwdriver to remove 2 screws holding the radiator fan shroud on, and remove the shroud from the radiator
5) Use an engine crane to lift the right hand side of the motor up (Hopefully you still have the oem lifting ring bolted to the head), the motor only needs to come up a few inches, to allow enough clearance to remove the mount and its bottom bracket from the car
6) Remove mount and lower bracket from car, then mount the bracket in a vice.
7) Use a 17mm socket to loosen the nut securing the engine mount to the lower bracket, remove the old engine mount (note the orientation of it before you do this and have your new mount lined up ready to go on). Give the mating surfaces on both brackets a quick clean if needed.
8)Fit new engine mount to the lower bracket, take note of the stub, there is a dimple on the bracket where it sits. tighten the nut to secure it to the bracket, my new mount uses 15mm nuts
9) Fit new mount and lower bracket onto your car, line up the studs as best you can to their respective mounting holes on the top mount bracket, and engine crossmember.
10)Carefully lower engine crane while ensuring the studs on the mount and bracket still line up (assistance is handy here) If all goes well it will all line up perfect once all tension is released from the crane.
11) Refit and tighten the 17mm lower mount to crossmember nuts, and also the 15 or 17mm top engine mount nut
12) Refit fan shroud, engine splash tray, reconnect your battery if required.
Hopefully that helps someone out.