This was a tougher matchup but the defending champion emerged with a 6-4 5-7 6-2 victory.
Cranston and Lawrence were fairly comfortable on their march to the mixed doubles crown, beating Raewyn Watson and Richard Owen 6-0 6-0, Elley and Allan Wilkins 6-1 6-1, followed by Marietta Duffy-Burgess and Howard Lewis 6-2 6-3.
Cranston was joined in Napier by follow Wanganui Tennis Club members Relwyn Hooper and Sean Edmonds.
"Relwyn played really well and came runner up to a very highly ranked Japanese player in the men's 75+ singles," Cranston said.
Hooper beat Keith Burt 6-4 6-2, then Max Brown 6-2 6-3, before losing to Japan's Noriji Kataoka 6-0 6-0 on Monday.
He would get a measure of revenge, teaming with the Aucklander Brown to beat Kataoka and Bill Thom 6-3 6-3 in the men's 75+ doubles, but they would not claim the title as a victory of Tony Cotton and Owen Passau 6-4 6-1 was followed by a loss to Burt and Gary Pike 6-4 6-2.
Cranston said Edmonds got a wake up call at his first national championships.
"He won his first singles and then came up against a New Zealand representative who showed Sean a thing or two about nationals."
In the men's 45+, Edmonds turned the tide to beat Vikram Nagpal 4-6 7-6 6-0, but lost to Steve Buckmaster 6-0 6-0.
Edmonds teamed with Simon Yock to play in the consolation men's doubles 35-45, winning one and beaten twice.