I got my engine machinist to tap the two holes and put Allen head grub screws in there, then he staked around them so they wouldn't come out.
I don't now how critical it really is, it just looked like it made sense to me.
I bought the plate to block off the EGR and also had to block off the hole on the opposite side that also looked related to EGR, you can buy a genuine part to block it off but once again for that particular part the shipping to NZ was quite a lot so I go the machinist to make something, I suspect I didn't save much in the end.