Thanks folks,
@Gordy ~ we work in remote locations around England & Wales, so can't purely rely on GSM comms as we rarely have signal.
To make the solution a little cheaper I guess we could opt for the message / tracking then clarify the task via GSM / intercom. However i'd prefer to have it all via one box of tricks.
Can't decide whether to have a handheld device for both crew members (usually 2 of) or a built in system. With a handheld even if we are away from the heli we can still communicate.