Adapting conventional forces to fight the Death Eaters

How could the British military help defeat the Death Eaters if the government knew the wizarding world existed?

Combine friendly wizards with surveillance and conventional forces, while studying defenses against hostile magic.

In this Harry Potter scenario, a British military response would need friendly wizards to help protect personnel against magical compulsion. Snipers and thermal cameras are proposed alongside that assistance. The discovery of magic would prompt study both from people interested in its possibilities and from people who feared it. Protective measures would need to be developed, including ways to prevent charms from disabling equipment. The extent of those possible defenses would require investigation.