Topic

No the torx bit has 6 lobes, they’ve a bit more radiused to allow more torque to be applied, the normal torx bits can be used on torx headed bolts with care (not a real good fit) but the Torx bits cannot be used on normal Torx headed bolts.The 5 lobed bits mentioned are tamper resistant Torx+ bits they have the central pin hole as opposed to the normal tamper resistant torx bits which have 6 lobes and the pin hole.
To confuse matters there are 5 lobed solid bits that are pretty well the same as Torx+ tamper resistant bits without the hole.

There are a bewildering array of screw head types, you can read more Here

I think that original questions should have an outcome wherever possible so here goes.

Now that the HG is done, time think about the horns again.

When pressing the buttons, a click is detectable from the centre console. I think this confirms buttons, rotary coupler and relays are all working. And fuse OK.
#2 son has a Fluke with needle probes do we confirmed 12V at both horn plugs when buttons pressed. Those plug sockets are tiny.

Who would have thought that both horns are OOS. 2 used ones on order from MGFnTFBitz.

Epilogue to be reported.

And in closing, 2 horns from Bitz both work. End of.
Who would have thought both fail at once.

If its a TF, then it will be one of the relays in the BCU (body control unit) Technozen electronics will sort it for you.

Thanks Mr Young. I thought the same and even bought the 5 star Torx bit.
It was the horns themselves. Both. At the same time.......