peculiar rack bolts?

[Withnail]

The rack/bulkheadmounting bolts on my B5 have a male 12pt spline head. It's nae bother, since I replaced the rack years ago, but the only thing that fitted at the time was the business end of a cheap 10mm ratchet spanner (welded into the end of a scrap 3/8" drive socket in order to make it useable). Other 12 point / bi-hex spanners of the same size wouldn't go on. I don't think there are any other fittings of the same type on the car and have never seen mention of this. Is this some special kind of fitting?

[olds_kool]

any 12 point socket will fit, halfords pro are all 12 point (the only thing i buy from there are tools)
the first time i saw them was doing my old mk1 golf clutch, thought ive got nothing that will remove it but tried a normal 12 point socket and it was a perfect fit