Is this polytunnel doomed?

I've been trying to get the polytunnel lined with bubble wrap to keep the heat in and the rain out but the roof has been proving a problem! Using bamboo from the garden, will weaving it through the roof supports be enough to keep the bubble wrap in place?
CHALLENGE (and follow up) - we had heavy rain yesterday and I can honestly say the bamboo DIDN'T work the way I had planned! So I need your help - how can I get the roof covered with bubble wrap but not fall in every time it rains?!
The polytunnel (and the video) might not be the most professional looking item on Rumble but it does the job!
*See video about how I made it to find out why the rain comes in through the cover if it isn't obvious from this one!*