You could search your DW configuration for that file and copy it from there.
It should copy it as it writes the file to your page. Make sure the page you add it to is saved and in a php defined site and it should copy the file automatically.
I have tried adding it to many pages throughout today and on two computers - my desktop and laptop and neither is playing ball! The whole site is php which as I said in my original post was built some time ago.
Can you elucidate a little more info on just where I might find this file in the DW configuration, please?
I'm just a little bit desparate to sort it for a client who cannot now, for reasons beyond me, access and update her site.