Joint overnight leader Minna Kaarnalahti (Finland) slumped to a second-round 83 while Laura had another sub-par round, a 72, for a 36-hole tally of three-under-par 143.
Kaarnalahti is out of contention, it would seem, barring some sort of miracle. She is now tied 12th of 154, 11 shots off the pace.
Webb had birdies at the short second, sixth, 16th and 18th in halves of 34 and 38. She "wobbled" a bit early on the inward journey, bogeying the 11th, 14th and 15th but her birdie-birdie finish ensured she would have a clear advantage with 18 holes to play.
Defending champion Julie Brown (Trentham) is her closest challenge on 148 (73-75).
Julie had only one bogey in the first round but four of them today. She birdied the short second but bogeyed the fifth and ninth in 37 to the turn. Brown's inward half was also a mixture - a birdie 4 at the long 12th but bogeys at the 13th and 14th which extended the gap between her and Webb.
Still, at least Julie will be playing with the leader in the final round and will know what she has to do, mainly a strong start and hope that Webb starts dropping shots.
Former champion Ann Lewis (Royal St David's) and Sweden's Christin Moller are sharing fourth place on 149. Ann has shot 72-77 with an inward half of 41 today. That included a double bogey 5 at the short 10th. Christin birdied the first, 12th and 17th in halves of 37 and 38.
Minna Kaarnalahti never got going at all with a second round of 83, 12 shots more than her first-day effort. The Finn had two bogeys in her opening 71 but nine of them plus a double bogey in her second round. Minna bogeyed the first, second, fifth, seventh, eighth and ninth in 42 to the turn ... and it did not get any better. She bogeyed the 10th and had a double bogey at the 11th. A solitary birdie at the 15th was followed by bogeys at the 16th and 17th.
Ireland's Gertie McMullen (The Island), runner-up, last year had not a single birdie over the first 36 holes. Her scores have been 79 and 77 for 156.
The cut fell at 160, with Alison Murdoch (Canada), 83-77, and Susan Dye (Delamere Forest), 80-80, making it with nothing to spare.
Catherine Rawthore (Sale), the 2014 champion, missed out by one shot with scores of 80 and 81.
Pat Doran (Donabate), with 82 and 81, was another name player to miss the cut.
North Berwick's Dawn Young had her first ever hole in one at the par-3 eighth (133yd) with a six iron. "One bounce and then in the hole," said a delighted Dawn who missed the cut with rounds of 87 and 80 for 167. The eighth hole is the LGU’s designated “Birdie, for Breast Cancer Now” hole where the LGU donates £2 per birdie throughout any of the stroke play rounds and £50 for a hole in one.
CSS 75 - Round 1 - Wednesday 14 September
CSS 75 - Round 2 - Thursday 15 September