I thought the same thing. You omitted very important information. The logo is not showing your survey (at least when I tested it), but on the index page. So you need to adapt the template for the index page as well, as Jelo highlighted.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.