The Ashes: I've put Aussie woes behind me, says Ian Bell

Chris Rogers is caught by Matt Prior off the bowling of Graeme Swann (REUTERS)

Ian Bell believes his three centuries against Australia this summer have banished all memories of his early struggles in the Ashes.

Bell scored only two half-centuries in the 2005 series and, although he performed better in the following one, he was part of a side whitewashed 5-0 Down Under. The batsman contributed to the triumphs in 2009 and 2010-11 but his performances this summer have easily surpassed all of those.

After his hundreds in the victories at Trent Bridge and Lord's, Bell will resume today on 105 not out, having helped England into a lead in excess of 200, with five second-innings wickets still standing.

Bell went 30 innings before scoring his first Ashes hundred but now he has four in his last five Tests – three in this series and one in the final Test of the last, at Sydney in January 2011.

He said: "I believed I was good enough to score Test hundreds against Australia but it took a while. The first two series I played were against one of the best of all time. For a young player, that was a really tough baptism and I learnt a lot from great players. I've had to work really hard in this series, too.

"We've got a lot of respect for this attack and we're always challenged when we're batting. But it's enjoyable to score hundreds and maybe put to bed some of the stuff I've done in the past.

"This is right up there with the best form I've had in my career. If we can get a lead of 300 we will be more confident, but this Australia team keep coming at you."

This was Bell's 20th Test hundred and, comfortingly for England, they have never lost a Test in which he has reached three figures. He has built the platform from which they will try to take a 3-0 lead in the series and win the Ashes outright after last week's draw at Old Trafford ensured they would retain them.

Australia will be desperate not to allow England's lead to extend too far past 200 – it was only 17 when Bell walked to the wicket but is now 202 – as they seek their first Ashes Test win since Perth in December 2010. They are also anxious about the fitness of all-rounder Shane Watson, who was unable to complete the second over of his second spell and left the field after delivering the third ball of it.

Cricket Australia reported that Watson was suffering from pain in his hip and groin and would be assessed this morning. With no runners allowed in international cricket, the tourists will be worried about Watson's ability to bat. He had struggled for form in this series but scored 68 in the first innings after dropping down the order to six.

Ryan Harris, who removed England's top three batsmen, was hopeful Watson would be fit: "It might not be as bad as first feared. When I left the dressing room, there was talk about him batting. He was disappointed for a little while after he had to come off but hopefully we'll get good news and he'll be ready to go."