Hello Glen,
Thanks for writing in! To make sure that the logo and your custom content next to the logo appears neatly in smaller screens, please have your code updated and add the following css code in the customizer, Appearance > Customize > Custom > CSS at the very end of your other custom css
@media(max-width: 767px){
.masthead .x-logobar {
text-align: center;
height: auto !important;
}
.masthead .custom-phone-container.right {
float: none;
position: relative !important;
top: auto !important;
right: auto !important;
padding: 10px;
}
}

Hope this helps. Please let us know how it goes.