To start with if Dore and his wife had planned the whole thing as an elaborate act of revenge wouldn't they be a bit perturbed when world-famous mystery-solver Jonathan Creek turned up? Isn't he likely to spot what's going on? So when Jonathan and Joey get trapped in the coal cellar wouldn't it be more likely that Dore or his wife trapped them in there on purpose to keep them out of the way instead of it being the accident that it was.
This means that the Dores didn't know that Jonathan and Joey are conveniently out of the way they should have been worried that they might show up in the middle of the 'murder' and spoil the whole thing. Added to this weren't they worried that Emily might also show up in the garden in the middle of the 'murder' when she was supposedly in the upstairs room pushing Mrs Dore out of the window. Their plan depended on split second timing and they seem to have left everything to chance for it to work which is unlikely for two intelligent people.
Also we learn that in order to plan their revenge the Dores managed to trace both Emily and her friend. Then Mrs Dore had the wherewithal to kidnap Emily's friend, keep her (drugged?) in the coal cellar and then kill her at precisely the right time in order to use her for the elaborate fake murder scene. And she also had to remove her from the cellar so she wasn't there when Jonathan and Joey started searching the place. And the business of ensuring the body would land on the railing spikes. How on earth would they rehearse such a thing? All that demands a huge stretch of the imagination, more than I think even the most gullible viewer has.
Also after the murder how did the Dores know that the two witnesses would both go inside enabling them to switch the bodies back? If one of them had stayed their plan would have been scuppered.
Plus are we supposed to believe that for the sake of executing revenge on her husband's brother's killers Mrs Dore was prepared to live the rest of her life as a recluse with no contact with her family sand friends? Or were they in on it as well?
Also I was confused by the the role of the priest. I thought at first that he was C of E but the fact that he took confession means he must have been Catholic. Do they normally have such Catholic churches in rural England? And at the end were we supposed to think that Dore killed the priest to stop him from reporting what he thought he had heard to the Police?
If the place where the Judas tree is planted is where Emily and her friend killed Dore's brother wouldn't Emily have recognised it from the map she finds in their office?.
Emily does not look anywhere near old enough to be twenty years older than she was in 1988 and it didn't help that the younger Emily was played by an actress that looked nothing like her. That only served to confuse matters further.
In the Victorian legend they never explained how Selima had the ability to fill the Doctor's watch with HCN gas. Was she both a scientist and an engineer? And how did she find an exact replica of his watch to make the device?
Of course fanciful explanations and occasional inconsistencies are all part of the fun of Jonathan Creek and normally I would ignore them but usually the chemistry and comedy between Creek and his collaborator make up for it. Sadly the comedy elements in this episode were rather forced and frankly unfunny. For example the scene in the cellar where Jonathan relieves himself in the cat litter. If all he was doing was having a pee why didn't he do it straight into the bag? Also the scene where Mr Dore comes to the neighbours house to hide the pipe and Jonathan and Joey are forced to hide. This is only done so Joey can get stuck in the vase. Considering they had just learned how Mrs Dore had hidden from Emily in the bathroom why didn't they just do the same thing? (and regarding hiding the bamboo pipe, wouldn't it have been more fun if Dore had placed it in one of the numerous pot plants there as a cane, that would be a more JC-style solution than hiding it in a drawer).
Also the scenes where Jonathan picks Emily up at a bus stop and takes her back to a hotel room were not only unfunny and highly unlikely (Creek is too uptight to be so spontaneous) but were also unnecessary as they did nothing to serve the plot.
When David Renwick is on form he is excellent but when he is not it is somewhat embarrassing to watch. There were a few One Foot In The Grave episodes which suffered in a similar way but this perhaps is the worst yet. Of course it may not be entirely his fault but whoever is responsible I hope they consider more credible plots and funnier sub plots in any future episodes.