Theory:Doctor Who television discontinuity and plot holes/Heaven Sent

• The obvious one. If all the rooms in the castle reset - how is the Doctor able to slowly wear down the diamond wall over multiple incarnations?

At a guess the resetting stops when the Doctor 'dies' and begins again when he 'arrives'. So the settings are as they were when he begins the loop again (all the rooms would have been rest by then to their 'normal' settings). The diamond wall room is occupied when the Doctor dies so the resetting stops when he has done some damage and stays that way until the loop stops with him inside it again. You may ask why, if this is true, do the bloodstains on the floor dispensary, to which I can only answer that maybe the floor is independently self cleaning?

• 1) who put the very first costume in the fireplace room? or the first 12th doctor just put off the wet one, left it and went on naked? otherwise there'd be no extra costume for the next 12 and why didn't it disappear when the room was reset? even if it's not supposed to be gone because it's like a part of something alien-not-castle-stuff, still the question stands - who put the first costume in the room?
• 2) what was the point in taking the panel from the floor, writing on it and burying in the garden? and if all the rooms except the wall one get reset, why the garden and the floor weren't reset? The garden was only reset to the grave being dug up back again, but that's not what it was like when the Doctor first got there. Or in fact he wasn't who dug it, the Time Lords were, so the dug up grave was a default? Why? To show him the way? But why so complicated?
• 3) if the rooms are being reset all the time, why the word 'bird' stayed on the sand for a while for the Doctor to read it, and was gone later? And why the castle started moving and opened a way to the roof when the Doctor saw this word? The Bird clearly means no good for the timelords, more like vice versa.