On my Saab 93 convertible the hooks that hold the roof down at back have ceased operating.Ideas?

I have had the car for 4 years and the roof has become a little sluggish recently and is prone to 'soft top failure' needing a bit of manual help. Now the fastening mechanism where the back of the roof is locked down is not operating. Obviously I want to avoid any Saab main dealer. Any suggestions welcome.