Scam - when I picked up they claimed to have called a wrong number and hung up - very shortly after received a number of other scam calls so I think this one was testing if my number was genuine
They knew a fair amount about me and were telling me about the government pension review service that will tell you where all your old locked employee pensions are and fees charged, and move them all to one private pension pot. She rings ALOT!!! The number she gave me is a government number I checked that one out. Not sure if she is legit though or not.