Hello Ben.. I can't say as I've performed the belt slice thing, but you need to know that there's a locking screw on the side of the pump. The photo is stock off the internet, but you can see the locking screw on the main boss of the pump.
You undo the locking screw with your old belt and timing set up in situ, remove the spacer bracket on the locking screw, and then put the screw back in and nip it up. This will lock the pump in situ allowing you to remove the old belt and fit your new one. Don't forget to remove the locking screw and refit the spacer bracket once the new belt is on. Its critical of coarse that the engine is not turned in any way.
Re the idlers and tensioners, if you don't know how long they've been in there I'd change them.
If you require a PDF on the set up of this pump PM me with an email address and I'll send you one.
Dave..
