I liked it as well. There are no end of "realistic" detective stories but few have the wit of this episode. True, the 'it was all a dream" was a major let down; I would have had a Victorian episode with no more rhyme or reason than that first 'Alternatively'. Making it a dream also caused all the confusing back and forth towards the end, which we would have been better off without. But overall I tend to agree with the guardian reviewer who said 2016 TV is likely to be downhill from here.