Possible Clues:

• British, non-English prime minister's cool fighter
• Fighting not ever to get tight in a bundle
• Perhaps a doublet in a bundle makes it all offensive
• Gettysburg, for one
• Bull Run, for one
• Fight between opposing forces
• - - of 5 down
• You'd have to fight to get the teetotaller into the bundle.
• 'The race is not to the swift, nor the ... to the strong'
• Fight between armies