The plugs are both nailed and gued, so I'm a bit worried too!
The good thing is it did at least contain the explosion within the tube and the neighbouring tubes remained intact, even though the rack didn't.
I think I need to modify the racks so that the horizontal along the bottom does not come up higher than the top of the plugs. That way the tube will blow as it did but not take out the rack with it!
Talk first to your fireworks insurer! At Insurance Experts, Roy Musk does fireworks and his wife Angela does the motor insurance to carry fireworks. Other companies may be similarly competent.
Thanks Arthur.
I've spoken to my insurer but the cost has come back as quite significant!
I've been reading around quite a lot and found that many people have had luck with other van insurance companies, with them being able to provide them with a policy which includes the occasional carriage of fireworks for their business activity.
Can anyone share any companies that are willing o do this... I'm starting to hit-head-against-brick-wall!