Mk1 Hood tension cables

Can you change the tension cables in the roof without taking it off? if yes does anyone know how? I know the drivers side has broken.

Thanks

 Yes you can, although it’s fiddly getting the new one in - every wrinkle of the material works against you trying to feed it through.  If I had to do it again I’d try to find something springy (like an old bicycle brake cable) to use to run in a pullcord.
As I recall, the procedure’s just to remove the trim plate from the front edge of the roof and carefully peel back the corner of the roof material enough to uncover the anchor block on the end of the broken cable which is riveted to the front of the frame.  You need to drill out the old rivet, then feed the new cable into the channel in the roof material and hooking it onto the anchor spring at the back edge of the window before pop-rivetting the front end in place.  (Or possibly you need to rivet the front before hooking the back on…  Can’t remember for sure, but it’ll be easier to do the back first if possible.)  Then you just glue the corner of the material back in place and you’d never know it had been disturbed.