So it's going UK to UK?
Well, she's just wrong because I used to have my work's address as a shipment address on PP. So I think this is very odd indeed - she's clearly allowed to received personal mail at work otherwise she wouldn't ask for it be shipped there via email!
She could, if she wasn't being so awkward, ask you to send it for guaranteed Saturday delivery.
Send her the links I posted above - see what she says when it's in B&W !!
Its her own shop!!!!!
I am going to email her and give her 3 options
1. We cancel the entire thing and I refund
2. She waits for a day she will be home and I post the day before
3. She changes the address based upon the links above which I will send