I've bought a Grohe Rapid SL 3 in 1 concealed cistern and am about to start the stud work against the brick wall where it will be boxed in. I always thought that for these systems you need to put a shelf on top that can be removed easily for top access if something goes wrong, but looking at it I can't see what could actually be done from the top... surely any maintenance can be done by removing the flush plate? A lot of pictures I've seen online of wall hung toilets don't have access above them so I'm wondering if I can just create floor to ceiling studwork with no need for a shelf. Perhaps the original designs when these first came onto the market did need top access and something has changed since?