England assistant Graham Thorpe believes England's batting mantra can be boiled down to its simplest form: go past 500 in the first innings on a regular basis.

In the 35 Tests since Joe Root was appointed captain, England have only gone beyond 500 in their first innings on one occasion although there were some encouraging signs in the draw against New Zealand at Hamilton.

Root returned to form with a splendid 226 and Rory Burns became the first England opener since Alastair Cook to score a Test century both home and away as England got to 476 all out on an unresponsive Seddon Park pitch.

Captain Root and head coach Chris Silverwood have preached a message of patience at the crease from their top-order but Thorpe, who serves as the batting coach, thinks it can be uncomplicated even further ahead of the four-Test series in South Africa which starts on Boxing Day.

"We've talked a certain way about batting a long time and I think we mustn't misinterpret that, for me it's just getting a big first-innings score and that's a 500 target," Thorpe said.

"That's a good way of selling it to the players and that's what we're looking to do."

While England's efforts in the second Test were not enough to level the series as New Zealand held on to secure a 1-0 victory, Thorpe insists the side are on the right track as they target a tilt at the Ashes in 2021/22.

"We're still very much a developing team from a coaching point of view, we're trying to identify those characters who can take us forward," the former England batsman said.

"We've got to keep developing our players, no doubt about that. They have to ask themselves when they come away from a trip like this: 'Where can I get better?'

"Because the big picture is down the line in a couple of years' time, we'll need resilient cricketers going to Australia."

Root ended a lean patch with his first double hundred on foreign soil. Before then he had averaged 27.4 this year to fall out of the International Cricket Council's top 10 Test batsmen.

Thorpe is confident Root can become the fulcrum of the batting line-up – in a similar vein to Steve Smith and Virat Kohli, contemporaries the Yorkshireman has been ranked alongside for much of his career.

"Yes, in many ways, but we also want that from other players as well within the group," Thorpe said.

"If Joe can produce more performances like that, we've got more chances of getting (to scores like 500). He's one player who can score big runs for us.

"It's great to see Root come back and scoring some runs and how he is in the dressing room as well, that's great for his confidence.

"But he was already held in very high esteem in the dressing room as well, so he's just confirmed that and also that he's a world-class player as well."

Thorpe, who alongside fellow assistant Paul Collingwood and Root were at the helm for the final days of the tour after Silverwood returned home early following a family bereavement, also had some warm words for Dom Sibley.

The Warwickshire opener was the only batsman in Division One of the County Championship to go past 1,000 runs, while he faced 1,009 more deliveries than anyone else in the top-flight.

However, he had a top score of just 22 in three innings and seemed susceptible to the short ball, while his tendency to favour the leg-side led to his downfall twice.

But Thorpe added: "I thought all the guys, (Zak) Crawley, Sibley, (Ollie) Pope coming back into the team, watching them go about their business in training sessions, I was impressed by that. That's a good sign.

"For sure they would have liked the right-hand column to say more for them in the couple of games they played but I've been impressed with the way they've gone about themselves."