As far as I'm aware L410s type certificate is not EASA-recognised so it cannot be in commercial service with G-reg.
RVSM is a joke, small turpoprops never making that high where they need RVSM.
TCAS installation represents a 30 to 50% of aircraft cost so many operators opt to lower MTOW in order to escape from TCAS.
It is indeed two man crew only.