To change to cavity doors you will need to remove the wall each side of the doors to accommodate the cavity housing. Normal sliding doors would make a difference but the problem with them is they never stay totally closed and they do become quite noisy and annoying. This problem also applies to double cavity doors. The other option is to use bi-fold doors, they won't intrude into the room as much. Do you really need two doors there at all and is the glass above the doorway necessary? My personal preference would be to fill it all in and just have the one door to the room. You could even re-use one of your doors.

Not a fan of the tall doors as they always look skinny. A transom/glass highlight above looks great in old houses though. 2700 is a nice ceiling height but not super tall. The std doors will be better in my opinion. The only time the higher doors look good is if they're a wide glazed sliding door unit but they should then be teamed with windows at the same head height! I've never been a fan of the starkness of std ceiling white. Ceiling colour and walls being same shade make cutting in easier to if you're not a professional painter.

if you decide to have a wall hung toilet or towel rails on the toilet wall the cavity slider wall will need to be reinforced to support the weight and a wall hung toiler with inwall cistern will mean that the cavity slider would have to slide towards the vanity..Either hinged or cavity slider doors will be good in this situation although the hinged door has the useful option for hooks for clothes or an extra towel rail...btw consider moving the master bedroom entry door for a more generous entry into the bedroom

SOOOO Annoying....I 100% feel your pain, I've had many "discussions" (read: confrontations) with builders about this - despite clear specification they just don't seem to get that seamless/concealed means we don't want to see that sliding door sticking out AT ALL.........Yes, you can fix it, but the problem with the less invasive option, (which is to pack out the frame so that the door is completely concealed) is the reduction in the opening width.......this detail to pull off well needs to be nailed down at framing stage/ordering of the cavity door units, because the cavity unit really needs to be ordered longer.......it's an expensive fix for the builder if they stuff it up - they'll try and talk you out of it, so if you had it in the contract/spec possibly it's a point of negotiation if there are other variations/extras involved... Good luck Kay! PD :)