I’ve actually found a quick and easy solution after speaking with @mufasa on another thread here:
In Engine Prime I set the BPM settings to 98-195 and the imported all the DnB from my list into collections and it analysed it really well and corrected the BPM so they are all between 172 - 175 now.
The beatgrid lined up almost perfectly on all including Onslaught although I had to shift it sometimes by 1 beat and the odd one a little nudge but it took no time to do.
I’m now creating an EP playlist of the tracks and will look into how to transfer that to my SD card and will see how well it syncs on the Prime Go 