Enlarging a Zip!

I can see all of you thinking the woman's gone mad!  You cannot enlarge a zip!  I needed a 24" (61cm) for a large cushion cover, they were not available in the shop I work in so I thought two 12" (30 cm) zips will work! 

Pin the zips with the top ends facing each other and overlap the spare fabric at the ends.  Insert the zip as you would normally.  Complete the cushion cover in the normal way.  You can put them in closer together if you wish I wanted the zips to fit exactly to the fabric.

This works for bags and cushions