You still get the discount online, yes, BUT the 'VAT Free' is quite misleading.
By law, you must pay VAT, so 20% (the current VAT rate) is deducted for the sale from your purchase total and then you pay VAT on that price.
I mention this because some people get confused when they purchase online but still see VAT charged on their receipt or invoice in a 'VAT Free' sale lol.
I don't know why some suppliers persist in calling it a VAT Free Day