Seat mounting bolts?

Does anyone know the correct size / where to buy replacement bolts to mount the seat/seat mounts to the car. (A 197)

I’ve pulled out the standard seats and replaced with buckets and for now used the standard T40 Torx to mount my SW Motorsport direct replacement seat mounts.

I’d like to replace them with some decent hex cap bolts as the Torx are horrible and I’m worried about knackering them every time I take one out.
TIA