Wirral had much of the territorial advantage in the first half but could not turn it into points and Sandal took the lead when Frewin went over.
With Wiral running out of steam after the break, Sandal started to dominate. Prop Luke Norbury drove over from close range before centre Joe Allott set up Frewin’s second, Mark Pease adding both conversions.
Briscoe ran on to a short pass for his first and then sprinted in wide out and Wirral’s last-minute score was just consolation.
Sandal are now four points ahead of second-placed Sale.
Huddersfield YMCA scored two late tries to earn two bonus points in a 36-34 defeat at Billingham and are safely in mid-table in their first season at this level.
YMCA shaded the early encounters to lead 10-7 but the home side then took control before a late rally gave them a fright.
Sheffield Tigers moved up one place to fourth – they are 11 points adrift of Sandal – with a 31-0 demolition of third from bottom Morley at Dore Moor, their third bonus win on the trot.
Tigers took control with two early tries by full-back Peter Swatkins, the latter converted by fly-half Tom Outram, and they increased their lead on the half-hour when winger Henri Packard raced over.
Packard crossed for his second try early in the second half, Outram adding the points. After a series of scrum infringements by the visitors, during which they had a player yellow-carded, Tigers were awarded a penalty try which Outram again converted.
Having led 8-3 for most of the match, Beverley conceded two converted tries in the final 10 minutes to lose 17-8 to Cleckheaton and leave them anchored at the bottom of the table.
A penalty by Phil Duboulay was followed 10 minutes later by a flowing Beverley backs move which culminated in a try for wing Goran Jelenic.
Cleckheaton came more into the game and Ross Hayden kicked a penalty to reduce the arrears before the break after Beverley had withstood some fierce pressure.
Cleckheaton gradually built momentum in the second half and breached the Beverley defence through two tries from forwards Callum Thompson and Jack Seddon.
They were both converted from wide out by Hayden and this not only provided sixth-placed Cleckheaton a well-earned victory but it also denied what would have been a deserved bonus point for Beverley, who have nine points from 11 games.