I see the following in the source of your page:
<meta name="twitter:card" content="summary_large_image"/>
<meta name="twitter:description" content="Graphic design company based in Doncaster, specialise in branding but also offers logo, graphic design, web design, social media, print, consultancy & more"/>
<meta name="twitter:title" content="Utopia Creative - Graphic Design - Doncaster, South Yorkshire"/>
<meta name="twitter:site" content="@utopia_creative"/>
<meta name="twitter:domain" content="Utopia Creative"/>
<meta name="twitter:creator" content="@utopia_creative"/>
There’s no twitter:img field so there’s no image in your card.
For information on why your card doesn’t update more frequently, check the troubleshooting guide.