An update on this -
I told BA that the 50% compensation was not acceptable, especially as the week has worn on I'm beginning to discover more damage and missing items than when I originally submitted the claim. And as I am replacing seemingly "low value" items such as my makeup and toiletries, I realize I probably low-balled their actual worth. They explained that this is policy without receipts. I explained that I could not submit receipts for items brought on my trip as they were in my bag which was mutilated and returned to me with about 1/3 of their contents missing, including the receipts.
While I agreed I would submit bank statements that might indicate the items were actually purchased, I explained many were bought with cash, particular items bought in London where I was trying to get rid of all my British pounds before leaving.
I then asked "did you even look at the pictures I submitted with my claim?" She explained no, she had not as they "take too long to load."
Red mist appeared before my eyes. They didn't look at the photos? They clearly had no clue how badly they had messed up.
Composing myself, I asked if there was a more efficient way to deliver my photos. I told her once she had seen them she would realize how complete and utterly unacceptable this was and how insulting my treatment was, especially as a "valued" gold member who flies Club LAX-LHR 4-5x a year. To someone who has retained BA loyalty while living in the US even though it would be more beneficially to be Executive Platinum with American and receive benefits like domestic upgrades, to someone who flies BA to Europe no matter how much another carrier would be more convenient.
She agreed I could email the photos (which I have uploaded to the internet, so their should be no problems "loading" via the internet connection at a large corporation)
I emailed the photos. I await her response.