Couple of points that i've noticed:
The delay on the mega menu appearing, although slight, is pretty annoying. Seems this is being done with a bit of JS? Causes issues during page load (which doesn't seem particularly fast), where the menu won't display until the page has finished loading.
The hover effect over menu items causes a blurring effect which again, is annoying. Probably the colour contrast, or my eyes being duff.
Page weight is a bit on the high side, not too bad on desktop browsers but people browsing on mobile might see poor performance (I haven't looked at the site on mobile, not sure if some images are removed etc to help with this).
The site isn't user friendly for keyboard users, no visual queues for focus as a basic example.
Bug:
Livechat seems to have a badly positioned white border when minimised?
This is on Safari, no idea if it's intentional behaviour of browser specific.
Looks good though