Sorry to hijack but I was tempted to get my wife to mail me her passport and biometric info and for me to send the documents.
I thought that's what you were doing anyway?
If you're doing things this way, then she needs to send her completed application package to you, not just her passport (the biometrics info is electronic so she won't have that).
She'll need to send you:
- her passport,
- stamped biometrics appointment sheet,
- online application form,
- Appendix 2,
- marriage certificate,
- her relationship evidence (phone bills, Skype call logs, email inbox, boarding passes from trips to see each other, letters and cards you've sent each other etc.) etc.
and copies of everything she's sending.
She will also need to send you the return packaging and the return postage waybill.
I think it will be 'simpler' for me to send her my documents from a postage-to-return point of view
I'm not sure if you'll have time to do that now. She only has 14 days for the documents to arrive in Sheffield after the biometrics appointment.
It's a bit late to be deciding to send everything to her now - you should have done all that before she applied online if you wanted everything to be sent from the US. Ideally you want to have all the application documents in your hands and ready to be mailed before you even start the online application.
So, if you are sending your documents to her now, you're going to have to spent a lot of money (maybe £50-100) on fast overnight delivery by FedEx/UPS/DHL to get them to her (and hope they arrive within enough time), and then she will have to spend even more money than that to mail them back to the UK again for visa processing.
So you risk the documents not arriving in time for her to get them to Sheffield, and if that happens, the application will become invalid and you could lose the entire £851 visa fee and have to start the application process from scratch all over again.
Best thing to do now, assuming she's already done the biometrics, is for her to send everything to you and then you just forward it on to Sheffield for her. It will save both time and money on shipping.