JSFiddle - React, Tailwind, and code Playground

HTML

<div class="sales_block_one">
    <span class="sales_box_option_set">
        <input type="checkbox" value="1" id="exopt10i11553501716" name="optset[0][id]" />
        <label for="exopt10i11553501716">Test  + &pound;100.00</label>
    </span> 
    <span class="sales_box_option_set">
        <input type="checkbox" value="2" id="exopt11i21553501716" name="optset[1][id]" />
        <label for="exopt11i21553501716">Test  + &pound; 200.00</label>
    </span> 
    <span class="sales_box_option_set">
        <input type="checkbox" value="3" id="exopt12i31553501716" name="optset[2][id]" />
        <label for="exopt12i31553501716">Test 3 + &pound;400.00</label>
    </span> 
</div>

JavaScript

$('.sales_block_one :checkbox').change(function() {
    var $self = this;
    //$self.checked = true;
    $($self).closest('span')
        .siblings('span.sales_box_option_set')
        .find(':checkbox').attr('checked',false);
});