I watched both
Karaoke was excellent and Cold Lazarus was okay. I agree that Finney was outstanding.
My hearing is not good and I am stone deaf to certain tones. I had some trouble keeping up with some of the memory flashbacks in CL. I was a bit confused regarding his twin brother and their relationship.
CL is typical Brit science fiction. We love it like an old house, warts and all. I don't have a problem with cheesy effects, that goes with the Brit scifi, but I felt the story/script had a lot of room for improvement.