Walking and Scoring - THE GRQ PODCAST EP73

Walking and Scoring - THE GRQ PODCAST EP73  GRQOTW #72 Helen incurred two penalty strokes.  Stuart and Blakey cover: The role of a walker-scorer.  Setting up a course for both play by both professional men and women.  The second opinion.  GRQOTW for #73 - Gerry is playing Fraser in a match and on the par 3 17th hole at Wombat Hills with the match all square, Gerry hooks his tee shot into long grass. After Fraser plays his tee shot into a greenside bunker, Gerry plays a provisional ball which comes to rest 10cms from the hole. As they start walking towards the green, Gerry declares his ball lost and asks Fraser to not look for it. Knowing Gerry has a possible tap in for a 4, Fraser decides to start searching. As Gerry moves to his provisional ball on the green, Fraser thinks he has found Gerry's original balland calls out, "I have found it". Gerry taps his provisional ball in and replies with, "it doesn't matter, I declared it lost and I have putted". Fraser isn't sure of the Rules and requests a ruling - what is the ruling?