resizing logo on all pages except home, advice please.

Hi I was wondering if any of the experts could help me, i am completely new to this, I have my site just about how i want it but there are 2 things i would like to change but don’t really know how, the first things is –

I would like to use a smaller logo for every other page apart from the home page, i currently have a big logo for my homepage and am happy with that but id like a smaller one to be displayed when navigating away from the homepage.

the second thing is –

I would like to remove the annoying sidebar from all pages, I know there are other posts on this and it can be achieved with CSS but due to the different themes of peoples wordpress i have found the instructions impossible to follow in regards to my site.

could anyone help me with these things i would really appreciate it.

my website is https://www.swaggerinc.co.uk

thanks Sean