The Englishman, whose only European Tour victory came 11 years ago, had two birdies on the front nine and an eagle at the par five 12th to lead Australian Richard Green and France's Raphaël Jacquelin on nine under par.
“I have played great for the last two days so they have been relatively easy,” said Wall.
“This is a tough golf course and I have played really well again today. I haven’t really had a tough par putt for the last two days and that tells you how well I have been playing. If I can stay strong mentally then I should have a good chance to win here.”
Left-hander Green - at 64th the highest ranked player in the field this week - had six birdies in his 67 but a double bogey at the tenth denied him a share of the lead
Jacquelin played 32 holes without dropping a shot, but when he did he lost two with a double bogey at the sixth. However, he closed with two birdies in his last three holes to remain well in contention.
Overnight joint-leader Stephen Dodd was still six under after six holes, but Spain's José Manuel Lara, who held a share of top spot after round one, dropped back with a 75.
Former Ryder Cup Captain Colin Montgomerie remained in the hunt for a first top-ten finish for almost three years as the Scot compiled a bogey-free 69.
|T3||LARA, José Manuel||ESP||18||-7|