It looks like your contract may not explicitly say you are allowed to work remotely, so they want assurance from the company that you can do so. The bank statements should show the payments to your account from your employer, that should be easy to get.
They didn't ask me for a permanent address, in fact I added an address from an Airbnb and as proof sent the Airbnb visa document they provide in the site, no issues at all.
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