If I were you I'd do this way, you write as the director stating that your husband is allowed to work from remote and he won't have any issues by working remotely from thailand blah blah blah (u can find dozens of posts about it here). He needs to apply first as a remote worker and since the company is yours, it won't be an issue. Once your husband got is DTV you can apply as dependent (wife) but u need to be legally married.
I don't know how things are there in the uk, but here in taiwan it's mandatory to go to the immigration and get "2. CERTIFICATE OF ENTRY AND EXIT DATES from NATIONAL IMMIGRATION AGENCY (Validity 1 month)", that's also for the locals