What is the origin of the phrase "bo selecta"?

One explanation is bo is a gunshot, representing appreciation. And selecta is the DJ, the one who selects the music. So when the crowd say "Bo selecta!" they're giving appreciation and want the song played again.

From the Drum n Bass Dictionary:

Bo! - Simulated gunshot.. when a tune is big, say this loud if you want a rewind. In Jamaica people used to fire blanks all the time when a tune was big.

Booyaka! - an expression, like a gunshot.. say it loud when you want the rewind.

Boomshot - see booyaka, bo

Selector - A DJ, the person who is mixing records,

The phrase "bo selecta" was featured in the 1999 song "Re-Rewind (The Crowd Say Bo Selecta)" by The Artful Dodger featuring Craig David. In the song 'Gunman' by '187 Lockdown', the phrase "bo selecta" can also be heard.