The nature of the business we have is that stock is sometimes not kept on site and can be ordered in for next day, however we operate in a way that means our website displays as out of stock. Is there a extension that can change the "out of stock" to perhaps a button to call the store for a check of stock to then place a order over the phone?
I would suggest Amasty Custom Stock Status extension link
You can Add a link into those products , in your case add your Phone Number
