From top to bottom.

(2x) M12 x 42mm, 17mm hex cap with 2mm split lock washers. For both top and bottom of the bracket to the block.

Then,

M10 x 40mm, 14mm hex cap with 1mm split lock washer for top of the lower bracket from the cross member.

And sleeved through that is another,

M10 x 3" (76mm) locking 14mm hex cap and matching nut.

Everything is 1.25mm thread pitch.

And the bolt that connects the block to the roll stop is an M15 x 3" (or slightly longer if need be) with matching lock washer. Likely another 17mm hex cap. And make sure to use grade 10 where you can.

Note that I didn't physically have the M15 in my hand, I just measured the sleeve and as long as you have a 15mm shank by 3 inches or maybe 3.25" you shouldn't have any play.