if "anyone" can vie it then you can view it and look to see if it's possible to download your report to be printed or saved to be uploaded to the eVisa application
You wouldn't have your eVisa application assessed by the RTE London then so you need to consult the Embassy website serving the country for where you'd be applying from
because you cannot get a dependent visa from inside Thailand using a Non-O retirement visa. It is normally only issued if the retirement visa is a Non-OA which can only be purchased in your country of residence.
Were you married in Thailand because, if not, there are things you can do with your foreign marriage certificate before you travel to make getting your extension easier?