Defective by design.

The free ones that come bundled with things like mobile phone batteries are always entertaining. I have had some that are OK, but some are so bad you've got to despair of the human race wasting the Earth's resources to make them. T10 is a bit big for a mobile phone though.

They're in my assbox, so I do need the screws to remain functional.

The existing torx screwdriver I've got wouldn't fit even without the middle bit.

If I can spend £25-30 for a set capable of handling any encounterable screws, that'd be great - so long as they're not weak pound-shop-quality crap.

What do I need to unscrew this?

Step 1: Get Ireland to unite, team up with Scotland.
Step 2: Get them to take over the rest of the UK.
Step 3: Celebrate the United Republic of Ireland and Britain with tea and flapjacks.

:)

Can we please mandate that we should all have a southern Irish accent?

Because it's the best accent ever. (nod)

They can be serviceable (or even good) in a pinch: while on vacation last year, the mirror on my film slr got stuck*, an ongoing issue that can be remediated by unscrewing the bottom plate and oiling gears (as I learned from a web tutorial, except my body is an older and more simple model than shown).

I needed a very small phillips head screwdriver, so I bought a set of miniature screwdrivers at ye local dollarstore, and had the camera back in action in <1 hour.

*blocking the viewfinder. I took several more, perfectly good shots using the point-and-shoot method, to ascertain this would not dislodge the stuck mirror.

I was anticipating a video hosted by some young Olympian hunk.
 

I was unavailable.

Do you mean southern as in not-Ulster, or more cardinally (as in Cork, maybe Kerry, but not Dublin or Galway)?