I have a client who is in the process of upgrading their C5 site so it is a little more mobile friendly, unfortunately they don't have the budget to do a full blown responsive site yet, which means some of the site content will need to use the old site theme.

An example of pages that can't be converted yet would be some registration forms with pop-up information.

The client does not have the budget to make the forms mobile friendly, so the forms will need to use the old theme.

Here is a user case example - mobile user visits the site and see the mobile version, clicks on a link to use the registration form, a cookie is set using javascript to flag mobile theme disabled, so the user sees the desktop theme and form, but then the user uses the back button, or clicks on the home page link, because a cookie is set to not use the mobile theme they will see the desktop site.

So I am looking for idea's or suggestions for how to disable the mobile theme on specific pages, is there a way to set-up an attribute on a page that flags weather or not the page should use the mobile theme?

Any other idea's for how to set this up is appreciated.