Hi. Could you explain your rationale for these edits to college staircases?
Personally, I am not sure that the new solution is an improvement.
They are sui generis buildings. They don't have addresses, so I question the use of the 'addr' tag.
I think the previous use of 'name', while not perfect, is more appropriate, and certainly clearer for the user, especially because the staircases are mapped as distinct buildings. (If the whole building was a single area, with individual entrances mapped as nodes, I could see the unit approach working more, but that's a bigger change, and again, it would lose information more than add).

Hi. The house numbers here are already mapped from 1 to 43 with an interpolation line, which will automatically determine the mid addresses. Further details about the addresses should be added primarily to the end nodes.
See osm.wiki/Key:addr:*#Tags_for_interpolation_ways
Number 45 is mapped already as a separate building.

The building is mapped as a single terrace (osm.wiki/Tag:building%3Dterrace), with addresses as separate nodes. No address on the terrace is needed.

If you wanted to replace the terrace with a more detailed number of individual terraced houses, they will need to be drawn individually, with an address on each one of them. (The programme JOSM has some automated plugins for that, if you want to look into it). It would be more detailed, but it doesn't necessarily add much more information, unless the house are of significantly different sizes or shapes.

Note: The official legal designation remains the same.

Hi. I've fixed the multipolygon. The issue was an overlap of segments. Only the outer perimeter should be included, not segments in the middle.
The wiki page shows some examples: osm.wiki/Relation:multipolygon

In this case, because of how it was drawn, the multipolygon was unnecessary and I have removed it, leaving a shape for the building, plus building parts.

Thank you. That must have been from an older changeset. Now fixed, with normal values (I opted for good).
Best wishes.

Thank you. I got the wrong boundary. Fixed now.

I merged this with the already existing node for the sundial. I opted for an artwork tag, instead of a monument one (which refers to large structures).

Does the name refer to the whole thing, or it is just for the title of the plaque?
https://www.headington.org.uk/art/2012_armillary_sphere.html

Reverted.

Hi. I was just wondering if this is an information board, or perhaps a historic=memorial + memorial=plaque.

Wikidata and wikipedia should be prefixed with 'subject:', since the pages are about the event and not the mapped object itself.

Hi. Why unnecessary? The name refers to the overall area, having three duplicates is not correct IMO. If you had issue with its construction, then it would be better to edit its outer.

Hi, thanks for spotting this! I was able to trace back the changeset that deleted it — it was unrelated, so I assume the user did it by mistake. I've restored that original object, which had a more accurate geometry and better tags, and deleted your new replacement.

I've reverted your changes, restoring things as they were. If you think some of the bus stops are not correct, you can edit them again.

Editing the map is to update and improve the data for everyone. If you need to do something for personal use only, you will need a different tool.

You also deleted a cemetery. Please let me know if these were mistakes, and if you need help in reverting your changes.

Hi. Why have you deleted the roads under constructions in the new residential development? The Bing image is out of date, if that's what you saw.

(Sorry for the numbers of comments). Thinking about it, I think it will be more appropriate to map this as a mini-roundabout on a node, instead of the full loop.

Oh, I see what you mean now! Sorry. I was thinking of the roundabout mapped as a node. You are right, I will fix it.

What do you mean by "inside"? "sideway=both" means on both sides of the street (left and right), which is the case here: the sidewalk goes around the roundabout on both sides. Have I got this wrong?

Hi. A viewpoint is already mapped just nearby, where the bench is (there might also be a plaque?).
Regarding the name: Jarn Mound is more to the south (osm.org/way/55802655). Despite its elevated position, it is not currently a viewpoint, because of overgrown trees (at least last time I have been).

Hi. A gate can be mapped by adding "barrier=gate" to a node.
If people should not be walking down a path, it is probably appropriate to also add "access=private" to the path/road itself.

Yes, that makes sense. Done. osm.org/changeset/131742909