Rodney calls the man who sold Del the doors "Teddy Cummings" but later Del calls him "Tommy Cummings."
Del Boy's outfit changes completely between meeting Denzil in the market, and returning to the flat before the Trotters escape to the cemetery. He goes from a shirt\jumper combination to a red turtleneck and green jacket.
Del Boy makes a phone call. When he hangs up, the phone falls apart.
Wires are visible on the butterfly that Del and Rodney try to catch.
When the Trotters are in the cemetery, Del says that Grandad is in the garden of "external peace", which would mean he was cremated, yet in "Strained Relations (1985)", he was buried.