Kitchen / living / dining

room floor wall / pier laundry & fridge — coming out existing fit-out (indicative)

Overall

7.10 × 5.26 m max.

Depth: 385 + 50 + 201 + 25 + 47 = 708, against the 710 you measured on the party wall. The 47 is the net drop through the entrance steps (−37 + 40 + 44).
Width: 17 + 283 + 45 + 15 + 91 + 75 = 526, and the garden wall’s 414 puts the main left wall 112 in from the passage wall.
The 283 now starts after the 17 of the boxed corner, as you said — that was what stopped it closing before.
The entrance corner is a nib, not a stair. Up 37, across 45, down 40, across 15, down 44 — a 45-wide lump projecting into the room beside the doorway, which is the chunky pier in your photo.

The stub isn’t a chimney — it’s the end of the original house, and the plan backs that up. The 219 × 50 stub on the passage side and the 51 × 45 permanent pier on the party wall sit on the same line, at 385–435 and 367–413. Two remnants of one wall, left either side when the rest came out.
That makes the garden end an extension — roughly 414 × 385 — running 112 narrower on the passage side than the original house, which is exactly the step the kitchen sits in. It also explains the bulkhead in the ceiling over the kitchen.
Practical consequences: assume the stub is loadbearing until an engineer says otherwise, and expect different floor build-ups and insulation either side of that line.

It was measured from the window edge, not the wall face. Add back the 26 of reveal you weren’t counting and it comes to 112 — exactly what the garden wall and the bottom chain independently give. So the recess is 112 deep and the wall stub is 219 overall, 112 of it in the recess and 107 projecting into the room.
That was the last figure not tying to anything. Every dimension on the plan now closes against at least one other.

The circuit matches the plan exactly — garden doors → TV wall → fridge → hall doorway → kitchen → blind window → sofa wall → garden doors.
Kitchen window in the corner of the passage wall by the wall stub, looking straight at the fence.
Tall window with the wooden blind in the left wall, tight into the corner at the wall stub; radiator further along toward the garden.
Both windows sit in corners either side of the old external wall stub, not out in the middle of the walls.
Sink on the run under the old external wall stub, hob and extractor on the passage wall, prep on the run toward the hall.
Laundry enclosure is 75 deep, with one straight face running from the hall doorway right up to the fridge and a door in it. The fridge sits hard against the false wall — the long thin one — is coming out. Only the square block beside it is permanent, and that is the pier the new joinery is built around. The laundry is everything in there that isn’t the fridge.
No glazing on the party wall. Green cabinet and TV along it, then the enclosure at the hall end.
Garden doors are outward-opening French doors onto decking.

Fit-out positions are eyeballed from the photos, not measured — they show what is where, not how wide.

The bulkhead is a T, and it sits on the old wall lines. The crossbar runs along the original rear wall; the stem drops from it to the nib at the entrance corner. Those are almost certainly the downstand beams that replaced two removed walls.
Which means the kitchen pocket is not under it at all — the pocket has the full 2480. Tall units and 900 wall units are back on the table there.
It also corroborates the nib. A beam running to it says it is the stub of a removed wall, not a boxed service — so the original flat likely ended at the rear wall line with an internal wall running forward from it.

The crossbar clips the top of the storage wall run where it meets the party wall, so the pantry is capped at 2200 for its first 10 cm or so.
The stem crosses open floor. At 2200 that is 200 mm over your head as you walk under it — and any floor build-up comes straight off that.
Worth marking the actual extent on the ceiling; the widths here are drawn at 400 mm as a guess.

Widths and cill heights for the two windows.
The rise on the garden step.
A diagonal check across the main space — everything here assumes square corners.

Your cleaner floorplan

Walkaround

Kitchen: hob, extractor, boiler, window onto the fence.

Tall window with the blind; radiator further along.

Garden doors onto the decking.

Party wall: green cabinet and TV, no glazing.

Party wall running into the boxing and fridge.

Fridge, laundry door, then the hall doorway.

Entrance & laundry corner photos

Laundry alcove behind the fridge, the 75 door, then the hall doorway.

The nib beside the hall doorway.

The original sketch