Batch change date and time

I've got a large number of photos that for some reason have lost their correct dates and creation times, so I was wanting to fix them in a nice easy way. Unfortunately I've found out that Photos doesn't have the batch change option that used to be in iPhoto.

When trying to find a solution to my problem I came across this Batch Change the Date and Time to a Fixed Date, which works great, but not quite how I want it to. What I'm wanting to do is exactly what the above script does, but instead of incrementing by 1 minute per photo, I want to increment by 1 second intervals per photo.

Having not really used AppleScript before, I tried changing the references to "minutes" to "seconds" but that didn't work. Is it possible to do the above using seconds instead of minutes?

Any guidance would be greatly appreciated. Thanks.