Electrical storms in the area forced a delay of over an hour at Houghton Golf Club. Play resumed briefly, but the threat of lightning remained resulting in the suspension of the round. A total of 22 players will complete the third round on Sunday with the final round to follow.
Dredge held the 36-hole lead but struggled out of the gate on Saturday with a bogey at the opening hole. He recovered with a birdie at the second and drained a seven-foot putt at the par-5 third to make it two in a row.
The 29-year-old added a birdie at the seventh to reach minus-13 and was about to make the turn when the horn sounded.
Vaughan birdied two of the first three holes and moved to 11-under with a birdie at the seventh. He continued his fine play on the back side with birdies at 10 and 13 to move into a tie for first.
Anders Hansen, who had four consecutive birdies at one point, was at 12-under par through 10 holes.
Paul Casey, who had two eagles on his round, was one of many who were able to complete their rounds before play was suspended. He fired a 7-under 65 to finish in a group at 8-under-par 208 that features 1999 British Open champion Paul Lawrie.
Defending champion Justin Rose also completed his third round. Rose carded a 70 to move to 6-under-par 210.