This could be a QRF event taking place at Swynnerton.
I used to be in the army and we, alongside the emergency services and local journalists, would take part in a staged major disaster events in order to practice for a real event. These events often had police escorts & road blocks etc in order to make the event as real as it could be.
When I was i part of the QRF - quick reaction force - the events took place in the early hours of the morning in order not to disturb or inconvenience the locals.
In terms of the rockets, I'm not sure what that could be. I used to be in the air defence and we had missiles, later in my career we had a light gun, which is a big gun that you tow with a lorry.