Blyth completed the double over local rivals Ashington but were made to fight all the away against the much improved visitors to Plessey Road.
Straight from the kick-off the home forwards had their opposition in all sorts of trouble and were awarded a penalty which was put into the corner for an attacking lineout.
From the resulting catch and drive the ball popped up to Broadhead to dummy his way over, with Brookes adding the conversion.
The home side continued to press and it was fully 25 minutes before Ashington managed to get into the Blyth half.
When they did, and against the run of play, they were rewarded with a try in the corner.
The first half finished 7-5 to Blyth, but considering the home side had at least 80 per cent of the possession and territory they should have been out of sight.
In the second half the home forwards continued to dominate and increased the lead with a push-over try taken against the head, with Broadhead being credited with the touch down.
The third try was from another scrum taken against the head, and again Broadhead got the touch down for his hat-trick.
As the game entered the final minutes Blyth were totally crushing the Ashington pack and from a catch and drive they scored the bonus point fourth try, but the referee spotted an infringement by Ashington player and awarded a penalty try, making the conversion easy and giving Blyth a 24-5 win.
Next week Whitby are the visitors to Plessey Road for a 2.15pm kick-off.