I know Bp Williamson was a believer and there has been the repeated claim that Padre Pio wrote in support of
the apparition but just like the 3 Days of Darkness I've never seen the actual letter reproduced. It's one of those stories that gets repeated over and over online but there's little back it up.
This video that I chanced upon purports to offer some new info


Personally I lean toward it being false simply because none of the young girls pursued a religious life and 
it's my understand that some even doubted or recanted what they saw.
Does anyone know if the alleged seers have openly criticized VII or if they attend NO masses?
That would certainly shed a lot of light on the matter. 

There seems to be evidence that preternatural phenomena took place, including photographs and videos of the children doing things that would be extremely difficult, naturally speaking. There are also witnesses who say similar things, some of whom are still alive. Since it has many indications of not being an apparition from heaven, I tend to think it was satanic.