For England to fight back in this series against South Africa, it is simple - they need do virtually everything a bit better.

Their preparation for the first Test was chaotic and, although mistakes were made during the 107-run defeat in Centurion, England showed a lot of spirit on the fourth day.

They did not roll over. They did not hand victory to South Africa on a plate. They deserve a lot of credit for the way they fought, when all common sense was that they were going to lose.

Targets such as the 376 that England were chasing in the fourth innings are not made for a very good reason. To score 268 was a good effort.

It was not a nice pitch and England got some vicious balls. And if they had chased that down, on that pitch, South Africa's players would have gone away and resigned.

But, while there are positive signs for England to take out of the match, there are questions that must be answered.

How much did illness play a part?

There was no doubt that this was the most chaotic build-up to a Test that I have known. It was unsettling and unsatisfactory for England.

There was illness to the squad and to those outside the squad, and then players became ill during the game. They had players in different rooms and in different dressing rooms to try and isolate the illness where they could, but they have not been able to get rid of this bug.

Captain Joe Root said the illness was not an excuse for the defeat - and he is right - but I cannot think of anything that comes even remotely close to what this preparation has been like.

Seamers Stuart Broad and Jofra Archer had been in bed for the best part of a week before the Test with the bug, which made Root's decision to bowl first after winning the toss even more surprising.

I did not think at the time that it was the right decision to put South Africa in - and I still say that. There was some flawed thinking there.

Stuart Broad took five wickets in Centurion, while James Anderson took two

Who are England's best three seamers?

England at least managed to take 20 wickets for the first time in three matches this winter.

To do so, I still think their best chance will be a pace attack of James Anderson, Broad and Archer - despite Sam Curran's impressive 4-58 in the first innings this week.

England are protecting one or two players at the moment. All-rounder Ben Stokes does not bowl much these days - maybe a spell or two here and there - because of his knee, so Anderson, Broad and Archer are especially important.

Anderson, England's all-time leading wicket-taker, needed a run-out in Centurion after four months out with a calf injury, but England will also have to look at the lengths they bowled.

I do not think bowling bouncers with three men on the leg-side boundary - as they resorted to at Supersport Park - is the way to go.

Archer took 5-102 in the second innings but was expensive, conceding six runs an over. After an impressive start to his Test career in the Ashes this summer, England have not found the best use of him yet.

I would use Archer, England's quickest bowler, as a spearhead. If England are going to play five seamers as they did in this match, they can use Archer in bursts of three or four overs, so he can come back and bowl in an hour's time.

Spare him the long spells. Other bowlers can do that.

What about a spinner?

I cannot see slow left-armer Jack Leach playing the next Test in Cape Town, which begins on 3 January.

I do not think England trust him to hold an end up. It is something he has got more used to, but he was laid low in New Zealand with gastroenteritis and he has been really affected in South Africa.

He has Crohn's disease, which means he does not have much immunity to illness, and this one has hit him very hard. I do not think there is any way they can consider him for Cape Town.

Both Root and coach Chris Silverwood spoke about off-spinner Dom Bess, who was called up as cover for Leach before the first Test, and he will stay with the team for the second Test.

If they are going to play a spinner - and there is no guarantee they will - then Bess will be in consideration. He is a feisty competitor and he will also offer some support in the lower order.

Jonny Bairstow made scores of one and nine on his return to the Test team

Why pick Bairstow over Crawley?

Jonny Bairstow was dropped for the 1-0 series defeat in New Zealand before Christmas, when Ollie Pope was recalled to the side and Zak Crawley made his debut.

However, with Pope going down ill in South Africa, England picked Bairstow over Crawley in Centurion.

Although Bairstow made only 13 and 38 not out in the two warm-up games in South Africa, the decision to pick him for the opening Test was fair enough.

They needed some experience in the middle order and Crawley made only one in his only Test at Hamilton.

Playing Bairstow was the right call, but he has not done enough to overtake Pope if he is fit for the second Test at Cape Town.

Bairstow's dismissal in England's first innings was to a ball that stayed low. His one in the second, driving at a wide delivery, was not a good shot, and he will be the first to admit that.

If Pope, who made 75 in his most recent Test innings in New Zealand, is fit to play, England will go for him.