it seems caseworker has overlooked your documents.
Meanwhile, apart from waiting for your letter's response, you can also:
1. Drop a mail to Tier-1 customer care with your case docs, application reference number and ask for advice. you can also mention about the letter that you've already sent ( and royal mail tracking no., if any)
2. If you are not getting any response (in 2-3 weeks), make a complaint at
http://www.ukba.homeoffice.gov.uk/conta ... complaint/
regarding your visa, since your husband has got TIER-1, his work permit is no longer relevant but that does not invalidate his or your work Visa.
Moreover, you've also got home office communication in this regard, so nothing to bother.