In an indoor cricket net at Birkenhead Park in England's north, I am watching an extraordinary sight.

An 80-year-old man is drilling cover drives and pull shots in a way that makes him look like Don Bradman reincarnated.

Tony Shillinglaw is a Bradman evangelist. About 30 years ago, the former Minor Counties cricketer started teaching himself how to bat like the boy from Bowral.

"Here's a man who was 66 per cent better than anyone who has played," he said.

"I wanted to find out how he did it."

This sense of curiosity about Bradman came late in Shillinglaw's cricket career.

He was a local legend around the Liverpool district — he once dismissed England legends Ken Barrington and John Edrich in a Gillette Cup match — but felt like he never fulfilled his potential as a cricketer.

After being picked as a 15-year-old to open the batting for North of England schoolboys against the South, his game started to decline.

Sorry, this video has expired Tony Shillinglaw shows off his batting skills

Like Bradman, Shillinglaw was self-taught, but unlike The Don he did not persist with his unorthodox style.

The man Bradman considered the best bowler he ever saw, Bill "Tiger" O'Reilly, once said: "Coaches cause more damage than a sudden hail-storm."

In Shillinglaw's case, this seems to have been true. A well-meaning coach got in his ear and convinced him to change his style.

"Suddenly my bowling and fielding became better than my batting, because my natural instincts had been taken away from me," he said.

In his 50s, Shillinglaw began thinking about his unfilled potential as a batsman, and started studying Bradman's technique.

The world's greatest-ever cricketer had famously developed his skills playing backyard games in Bowral with a stump and a golf ball against a water tank stand.

"We found out that the key was the golf ball and stump — the ability to hit it and control it," he said.

"Bradman learned to control a fast, erratic, moving ball better than anyone else has ever done, and all I've discovered is you can't do it from an orthodox style.

"The only way you can do it is through rotation."

The water tank where it all started

The famous water tank as it looks today. ( ABC News: Steve Cannane )

The family home where Bradman lived between 1911 and 1924, at 52 Shepherd Street, Bowral, has been restored in recent years and is now open to visitors as a not-for-profit venture.

Its owner Andrew Leeming, who has a deep love of the game and its history, has even rebuilt the tank stand that was so critical to Bradman's development as a batsman.

On a recent trip home to Australia, I paid a visit to 52 Shepherd Street and had a go hitting the golf ball against the tank stand.

Immediately, you get a sense of how hard it is to master Bradman's backyard game.

The degree of difficulty is immense. You've got a thin stump to hit a tiny ball that is rebounding off a cylindrical brick surface at the base of the tank stand onto an uneven surface on the ground made out of recycled bricks.

The ball flies off this patchy surface quickly and you have very little time to react.

It's incredibly hard to hit the ball, let alone control where it's going.

Playing proper cricket with a decent-sized bat and ball on an even pitch must have seemed like a breeze for Bradman after playing his famous backyard game.

Sorry, this video has expired Steve Cannane tests his skills against Don Bradman's backyard game

Shillinglaw believes Bradman's old backyard in Bowral contains a goldmine of information about how to bat.

"Everybody knows about Bradman's record," he said.

"We were trying to locate the cause and the cause is the water tank and stand — [an] eight-foot space, golf ball and stump at Shepherd Street.

"That's where Don Bradman got his skill from."

The former cricketer has taken it upon himself to study and decode Bradman's unorthodox grip and backlift.

He labelled the technique the rotary method and has written about it in his book Bradman Revisited.

He cannot understand why Bradman's way has not been copied by all players.

"Jack Potter set up the Australian Cricket Academy. He knew Bradman quite well, so I asked him, 'has a study ever been done about Don Bradman?' He said 'no'.

"I couldn't comprehend it, and I still can't comprehend it."

After spending about 30 years studying what made Bradman the greatest, he wants to share his knowledge with the cricket world.

"We feel it's our duty that Bradman's method should be made available to cricket generally, and anyone with the aptitude or the will to do it should be able to do it," he said.

"Because it's not an idea that we've had, it's proven; the runs are in the book — Don Bradman put them there."