In 1963, one of the main characters, a wealthy, influential, and highly respected man, is accused by his maid of murdering his wife. The maid has some fairly damning evidence against him: a photograph she took which shows the accused burying a body in the manor garden. She's also able to describe the condition of the body to the police. The police, believing they have a solid, open-and-shut case, go to the manor to investigate and make the arrest...except they don't actually set one foot on the property. The accused, along with his equally influential and respected best friend, manage to so completely hamper the investigation that the police can't even access the manor grounds, much less dig in the garden. This continues for about a week, until the accused dies and the case is considered closed.
My question is: is there anything in 1960s British law, criminal or otherwise, that would have enabled them to keep the police at bay for so long? Possibly a loophole they could have exploited or rights they could have invoked? (These men were an engineer and a doctor respectively, but both were well educated and probably familiar with the law.) I've considered flat-out bribery, which they might have been desperate enough to resort to, but it's unlikely--the chief of police is so convinced of their guilt that, 10+ years later, he's still trying to implicate the best friend in the murder and is still upset that the accused man was never brought to trial. Bribing him most likely would have just backfired in their faces.
Any help anyone can provide would be useful; thank you!