Thanks for the great response Nick
I did a bit more digging and can see they are screws now. i only see them on one side though which confused me.
Thanks for the great advice. I will have a think and try to document what ever I end up doing. I might have a bash at removing them, cutting a new channel possibly in the head. Drilling them out and going for a bit bigger screw might work alright but as you say the wood under might be compromised.
I wonder how a metal pin would work epoxied into the hole. that way I would only be drilling the metal out and then inserting a plug back in.