You can install them in situ, Stephen. Easier if you remove the two front shocks as suggested above. However … there’s always a “but” … the remotes will be several inches below the original bleed nipple locations so you will be forcing air bubbles downward and they as a rule don’t like that very much. Worse than bleeding the clutch slave. I have found just recently if you pressurise the reservoir at about 15 psi and put the remote bleed nipple under vacuum before you crack it open the forceful rush of brake fluid carries any suspended air along with it. No peddle pumping (difficult with the rears in any event) and really quick.