Not an expert on this, but note that visitor visas cannot be used to apply for another visa. Visitors do not have any residency status and are expected to leave UK by the expiry date. Maybe this link could give you some pointers regarding inter country adoption: https://www.gov.uk/government ...

Im British and my wife is on spouse visa. My step child (her daughter, 8 yrs old) was left in Asia as I haven't reached Financial requirements yet dependent visa (I will do next year, but worried of the £38 increase). My question is, can I adopt my step child so we can bring her in the UK? My wife ...