HOW to stop Henry the mule wandering off overnight while David sleeps is one of many dilemmas David has had to solve since launching Operation Henry.
But thanks to John Wildman, research and development manager for WR Engineering in Plymouth, a pioneering solution has been found.
What is believed to be a unique tethering bore, has been designed and manufactured by the Devon-based company to help Operation Henry fulfil its goal of raising some £40,000 in aid of the Imperial Cancer Research Fund and the Macmillan Cancer Support charities.
The product is so effective that the company believes they could be flooded with orders for replicas of the corkscrew style lock and key mechanism.
John Wildman had to design something which would tether Henry by rope to a fixed point but allow him to walk around in circles without the rope becoming wrapped around the central point, decreasing in length and eventually injuring Henry. The innovative tethering bore was needed to prevent Henry disappearing overnight when David is asleep.
John Wildman presents the tethering bore to David Snelling
He came up with an innovative design, which is tough enough to bore into any type of terrain. The steel bore is in two main parts - a circular base plate which must be placed so it sits flush on the surface of the earth and a swivel bearing which Henry is attached to and which rotates freely so Henry can walk around in circles as much as he likes. The bore can be locked into the ground and cannot be removed without a specially designed key lever.
David said: "I approached WR Engineering as they are clients of mine and I like to do business with people who do business with me. They have found a simple, effective solution to a difficult problem, which is absolutely first class."
David believes equestrian societies, zoos and others involved in agricultural shows and animal husbandry will want to snap-up the product. WR Engineering is happy to make replicas or different sized versions of the tethering bore to cater for any animal from dogs and goats to elephants.
WR Engineering MD said: "We are extremely proud of John's work.
"If someone has an idea for something they want developed into a product then, providing we are supplied with some kind of sketch, then we have the ability and technology to design and manufacture it on site."
John Wildman of WR Engineering can be contacted on 01752 669050