I'd get 3 more gunsmith opinions on that .018 measurement.
I once had a Rigby 7mm Mauser I bought from a pawnshop in Vancouver many years ago. Yes, lots of retired Brits live there, brought their guns and rifles with them from India.
I brought it home to Winnipeg and had the local gunsmith's assistant check the headspace. The gunsmith was on vacation.
This moron took it off into the back, came out and told me the rifle had excessive head space, was not safe to shoot and offered me a used Remington 700 in 243 as a straight trade. No dice.
I never went back to that gunshop.
Always get a second opinion, always
Mike