I can't find a shop front website for them but you can buy large variety packs of small screws for specs and repair for a couple of pounds on eBay
Unlike Arno I decided against using any of the MBD bits supplied, as good as they were I wasn't happy with size and shape.
So first I established an angle for the tops of the horns and made eight pieces from 6mm that I topped off with flat strip.
They will all be fettled when assembled
I then made a shoe for drilling the base plate at the correct angle under the pillar drill
Working in stages to avoid ripping the styrene I finally reached 6mm
continued..........