The new alternator was delivered yesterday, so I set about installing it this morning. One lug for the pivot bolt is threaded and needs to be drilled out to 10mm, to allow the pivot bolt to go through both lugs.
The only way to get access to the top bolts is to remove a section of the air intake system and even then access is pretty limited. There is no way the alternator will come out upwards, past the radiator, so I also jacked up the car to gain access from below.
With the old alternator exposed, it was possible to undo the pivot bolt (from below) and tensioner mechanism (from above), to fit the new one. I don't run Yoko with a plastic floor pan fitted.
Fitting the new one is fairly easy and just requires the belt to be tensioned, viewed from below here. Once fitted, I did some testing and the voltage measured across the battery stayed at 14.5V regardless of engine speed. Job done!