REPLACE MAIN THEME LOGO – FOR ONE PAGE ONLY

Everyone has a different version, but nothing that quiet does what I need.
If someone could help me, I would be ever so grateful!

Basically, as with all themes, you can upload your own logo via the dashboard’s theme options. I’m using Cherry Framework with their “Theme50500”

Theme50500 is a child theme to Cherry.

I have a page, in which I’d like to change the logo for. Just that page.
It’s a responsive theme, so if you can suggest HTML div codes, please bare that in mind.

Also if you have suggestions regarding using CSS coding, please tell me which .php to put it in, if it’s the Cherry theme folder, or the Theme 50500 child theme folder, and where within that .php it’s meant to go? or can I just slap it down the end? as sometimes (Despite knowing a medium amount) it can start to look like another language..which I guess it is.. but you get the point.

Also bare in mind, in the child theme – there is no “Functions.php” but there is a “My_Functions.php” incase for some reason that’s part of the solution. And if the code utilises page_id, I can’t find the page id for the life of me, so could using the http:// work for the id?

Please please help.