I emailed the BBFC about The Guns of Navarone being reclassified from a PG to a 15.
They've come back to me to say that this was something that Netflix had done. they have a partnership with the BBFC and have the ability to rate films themselves using the BBFC standards.
Netflix has now amended their classification back to PG.
The BBFC guidelines include these comments on violence:
Works which feature the following are likely to be treated less restrictively:
â violence in a historical context
â violence in an action or fantasy context
â violence that lacks detail
â violence that looks unreal, fake or overly staged
â comic violence
â violence that is challenged or punished
â violence in a context where it is likely to be expected by the intended audience
Clearly the first 3 and last of those are relevant to the film and hadn't been taken into account by whoever at Netflix had classified it as a 15.