I would certainly expect a Lib Dem gain now, putting Surl's numbers in 2016 on top of the LDs would only require a small additional swing to pull it off. Which would be one of the first Lib Dem PCCs. Herts and Surrey also look strong for them this year.
Long Live King Charles!
“Under democracy one party always devotes its chief energies to trying to prove that the other party is unfit to rule - and both commonly succeed, and are right.”H.L. Mencken