Well, I will call them nearer the time and report back. Other embassies around the world make allowances for spouses but nothing is mentioned on UK embassies/consulates' websites.
"For company employee, an original certificate of employment, certificate of leave and an original copy of company's registration (tokibo tohon) are required."
Yes, of course I have read them. I guess I will have to ask them directly. As you know, every embassy has different requirements. The ones in her home country are basically impossible to fulfill (deliberately it appears). She has never lived in the U.K..