They may have won the Investec Test series with a game to spare, but head coach Trevor Bayliss believes England still have "a long way to go" before they can compete with the best teams in the world.

Bayliss was delighted with England's victory but knows that, with a five-Test tour to India before the end of the year and an Ashes tour 18-months away, his side "need to improve" in several areas.

Specifically, he believes that England need more potency in spinning conditions and accepts that there remains some uncertainty over the top-order batting.

"We are still a work in progress," Bayliss said. "We've a long way to go before we reach our best or a way of playing the game that I think everyone would be happy with. If we want to compete against Australia, who are the No. 1 team at the moment, on a consistent basis there are areas we need to improve.

"Our batting needs to improve against spin bowling. We did play well in the UAE against Pakistan so we know we can score runs. But bowling on the flatter, spin-bowling wickets, we can keep it tight but we've got room for improvement in terms of taking wickets."

Certainly England struggled to finish off the Sri Lanka second innings in Durham. While James Anderson ended with 5 for 58, the other six bowlers utilised claimed combined figures of 5 for 401. The spinner, Moeen Ali, finished with figures of 1 for 136.

But instead of calling for changes ahead of the final Test at Lord's, Bayliss explained that he felt that some of those players struggling for form would benefit from knowing that the selectors backed them and decided to name the third Test squad the moment the second Test was finished.

"There have been discussions over selection over the last month or so," Bayliss said. "But we have been about giving guys the opportunity to show us what they have got. The team has been winning so there is no reason to change it just at the moment. There's been a bit of speculation around one or two positions and we just wanted to let people know nice and early so they can prepare for the next match so there is none of that speculation."

While Bayliss suggested that, in an ideal world, he would like to "take a look" at Jake Ball in at Lord's, he also hinted that England may well name the same XI that played in Durham. Chris Woakes, he reasoned, could benefit from a rare opportunity to play two Tests in succession, while he believes Steven Finn could click back into form at any moment.

"In the two Tests Steven played in South Africa, he was probably our best pace bowler," Bayliss said. "And I fully expect him to get back to where he was in that South Africa series very shortly. We know the devastating bowler he can be when he gets it right.

"There no one thing you can tell anyone who's out of form or out of rhythm. It's about giving them as much support as possible and as much encouragement as you can.

"It would be good to have a look at Ball. But at the same time, it would be good for Woakes to have a few games in a row. He's obviously a very skilled player and if he can step up his game at this level with the ball and the bat he could play a very important role in this team. At this stage I'd have thought it'd possibly be the same team for Lord's."

One option might be to rest Anderson or Stuart Broad, now rated No. 1 and No. 3 respectively in the Test bowling rankings. But both will be keen to play in what looks likely to be a sell-out Test at Lord's and England's previous experience of resting them did not go well: Tino Best thrashed 95 from No. 11 as he and Denesh Ramdin added 143 for West Indies' tenth wicket at Edgbaston in 2012.

Admitting that Nick Compton's form was "a concern"- he has not reached 30 in his most recent eight Test innings - Bayliss made it clear that replacement options had been considered.

Bayliss mentioned Essex's Tom Westley - twice - Scott Borthwick, Daniel Bell-Drummond, Mark Stoneman and, after some prompting, Sam Robson as potential replacements. But sometimes it is the words that go unsaid that are the most telling; there was no mention of Ian Bell or Gary Ballance. He also conceded that he had not seen several of the options play and would be reliant upon the input of other selectors.

"There's a number of guys scoring runs," he said. "There's Westley from Essex, Stoneman and Borthwick from up here. Who else was there? Robson obviously, the young guy from Kent - Bell-Drummond, is it?

"To be honest I haven't actually seen those guys play, so I'm going to have to rely on the other selectors and what they think. Alastair Cook obviously plays with Westley, for example. But if they're thought of as good enough players and, more than anything, can handle the step up mentally there's no reason why we couldn't pick them.

"Going into Lord's with the same team just allows those guys to keep scoring runs over the next two or three county matches if we need to make any changes.

"But I'm quite hopeful everyone that's in the team at the moment can keep going forward because it's a good feel in the team and it's been a winning team."