Here's my experience: I just got my first BV- a large Veneta in the Copper Rame (Love Her!) Anyways, I am a big user of Appleguarde products, particularly the AppleGuarde spray and the cream leather conditioner. On my BV I gave it a light spray with the Apple Guarde Spray, and it was just great. No lingering smell, no spotting, nothing bad at all. I did not use the cream though, a little apprehensive given the metallic finish. HTH
I have a few veneta style bags and I was always told by BV associates not to apply anything on the bags. However, one BV SA told me that I could use Meltonian spray protectant.