When the attempt is made on Mrs Peel's life with the golf buggy, it tips right over on its side but when the view changes, it is at a 45 degree angle.
At 46 mins 15 seconds when Emma Peel is using the chair as a weapon the seat of the chair is seen falling off only for it to reappear in a fast edit while she is swinging it wildly. It then falls off a second time before she destroys it completely.
(at around 21 mins) Steed walks into darkness. Two seconds later he is standing on the fairway in daylight with no darkness nearby at all.
At 37:25 Mrs. Peel locates Orion and Leo on the same photograph of the sky as if they're adjacent to each other. In reality they're separated by 6 hours of right ascension, or one quarter of the circumference of the sky. Orion is a winter constellation and Leo is a spring constellation.
When Colonel Watson wants the periscope operated he calls out "Up scope" and "Down scope" as if he was on a submarine - but there is no crew to operate it.
In the drive-out at the end, Steed and Peel appear to be riding a golf-cart in a back-projection scene. Steed pours Champagne, then supposedly grabs to steer the cart, but his hand is too high in frame and can be seen not to have hold of anything.
When Steed and Peel arrive at the first tee at Craigleigh, they cast obvious shadows on the backdrop during the close-up.
When an explosion occurs, the people shown on the satellite TV screen move like they've also been hit by the impact.