lol. Well, I can certainly understand that

I think unless it specifically asks to show up in person, then you can deliver it for her.
Here's a post from someone who took in her own passport to London:
I went down the to London visa office this afternoon and handed in my passport. They gave me a receipt and told me to return in 2 weeks with the receipt to collect the passport with the visa. I'm glad I was able to do this instead of having to post it and wait after reading cases like yours. It seems almost cruel to take that long after finally getting through the rest of the process and getting the application approved.
You can find it
here. Seems to me it's practically the same thing as mailing it in, the only difference is there's a receipt that you pick it up with instead of them mailing it.
Perhaps you could send a message to Emmy or nabs, as they should have first hand experience. Maybe they can confirm our assumptions.