Meta slider loading issues

Hi there – I am using the meta slider on the home page of a website using the vantage theme (www.medina-aberystwyth.co.uk). My issue is that whenever the homepage is loading, the slider image loads in two stages. Initially if you head to the website the slider image only loads 3/4 of the way across the page. What am I doing wrong and what can I do to ensure that the slider loads correctly? Thank you.