Thanks for the help so far guys - I'll work on the contacts given ... and keep 'em coming.
Is there not an issue regarding mobile phones and avionics?
As for the safety issues, max height of f/works is 700 feet. On explosion they can climb an additional 200 feet, which gives a maximum height of 900 feet. We'll be 600 feet above that plus we'll be flying in circles outside of them rather than directly o/head.