What about the door? At the moment the bubbles hang from the sloping roof in
two pieces which part when we go through the door but if there's a better way
I'll be happy to hear it.

I'd suggest that you tape the bubble wrap around the door frame leaving a door
shaped hole in the bubble wrap to walk through. Then cut a piece of bubble
wrap to fit the door and tape it in place. This will keep the greenhouse snug
while allowing you to enter/exit the greenhouse without parting great expanses
of bubble wrap by hand.

I hope this makes sense, and good luck.

Dave.