I half-watched it while my OH watched it when it was on before, and did the same this time. Sheridan was fantastic and sounded very similar to Cilla. I can't say I was a fan of Cilla's tv shows, but she did have a great voice, back in the day.
No but by pure chance I watched/recorded all 3 episodes for the first time when they were shown in succession last Saturday night. Really bizarre as that was before the news that Cilla had died. I thought Sheridan was stunning and sang a lot better than Cilla. She treated her Bobby like poo in the early days though.