#t4-mainnav {
    width: 100%; 
    padding: 0px; 
}

.t4-section-inner {
    display: flex;
    align-items: center; 
    justify-content: space-between; 
}

.top-logo {
    flex: 1; 
}

.t4-mainnav {
    flex: 2; 
    text-align: right;
}

.t4-masthead .container {
  padding-top: 1rem;
  padding-bottom: 1rem;
}
.custom {
    display: flex;
    justify-content: flex-end;
    width: 100%;
}
<div class="t4-section-inner container">
    <div class="custom">
        <a href="https://www.linkedin.com/company/luminous-copywriting" target="_blank" rel="noopener" title="Luminous Copywriting on LinkedIn">
            <img src="/images/linkedin_white_trans.png" alt="" width="37" height="37">
        </a>
           
        <a href="https://www.facebook.com/luminouscopywritingservices" target="_blank" rel="noopener" title="Luminous Copywriting on Facebook">
            <img src="/images/fbook_white_trans.png" alt="" width="37" height="37">
        </a>
    </div>
</div>
}
.banner-image {
    height: 100px; /* Set your desired height */
    width: 100%;
    object-fit: cover; 
}
<img src="/images/emergency-management-communications-banner.png" alt="Two computer monitors showing maps and emergency management communications procedure" class="banner-image">

/* TABLE CUSTOMISATION */
.tblresp {
    width:100%;
    display:block;
    border:0px;
    border-collapse: collapse;
}    
.tblrespcell_50 {
    display:inline-block;
    width:49%;
    vertical-align: top;
    text-align: center;
}
.tblrespcell_25 {
    display:inline-block;
    width:24%;
    vertical-align: top;
    text-align: center;
}
/*.tblrespcell_25:last-child {
    display:inline-block;
    width:100%;
    vertical-align: top;
}*/
@media only screen and (max-width: 950px) {
  /* rules that only apply for canvases narrower than 800px */
    .tblresp {
        display:tblresp;
        border:0px;
        border-collapse: collapse;
    }

    .tblrespcell_50 {
        display:tblresp-tblrespcell_50;
        width:99%;
        vertical-align: top;
        text-align: center;
    }
        .tblrespcell_25 {
        display:tblresp-tblrespcell_25;
        width:99%;
        vertical-align: top;
        text-align: center;
    }
}