If you are meaning the 12 torx bolts needed for the bolt on shafts ( Lobro )
They are M8 X 50mm female head torx bolts, standard metric thread.
The ones I removed from mine are black in colour so I assume they are high tensile bolts 10.9 grade !!??
You may have a problem finding torx bolts but allen bolts will be just as good.
There are some allen bolts on ebay at the moment. M8X50 12.9 grade but they look to be set bolts.
I did message this seller a while back to ask it he had bolts of this grade & for a price of 24.
Sadly he never got back to me.
Nice to have plenty of trade & be able to ignore genuine customers.
I have not got a clue as to where you will find the little backing plates though.