Needing a “proper” way to hold the rolling roof in place I had a hunt around and found these latches:
I bought them from Amazon, but they seem to be pretty much everywhere. There are a number of different sizes and I bought the largest ones I could find, thinking that if I needed a longer one I could just join an extra bit of 6mm threaded rod onto the end of the existing threaded section using a connector nut.
When they arrived I decided that by making a small wooden mounting block to fit on the walls I could use the latches unmodified, so that’s what I did. Initially I put two in place where I had already lined the walls and then removed the sash clamps holding the roof down, fitted the remaining lining and finally fixed the last two in place.
The roof feels fairly well locked down with all four clamps done up (the “hooks” are mounted on the steel frame of the roof). If I get to the point of motorising or even automating the roof I’ll probably leave them undone, relying on the motor mechanism keeping the roof in place for most of the time, just using the clamps when windy weather is expected.