Slow website

Your biggest problem is the total page size:

https://gtmetrix.com/reports/www.concept8media.com.au/UcjPGYXh

https://www.webpagetest.org/result/170305_AX_B30/

This is why your site may appear to still load just fine on faster connections (2.8 seconds for myself, 2.6 for Pingdom, and 3.8 for GTmetrix), but not so well on slower connections (20 seconds for yourself and 38.3 for WebPageTest).

Specifically, these three images:

http://www.concept8media.com.au/wp-content/uploads/2017/02/chris-lawton-172561.jpg (6000 x 4000 pixels, 7.1 MB)

http://www.concept8media.com.au/wp-content/uploads/2017/02/clem-onojeghuo-192729.jpg (5400 x 3675 pixels, 6.3 MB)

http://www.concept8media.com.au/wp-content/uploads/2017/02/mario-calvo-355.jpg (5340 x 3588 pixels, 4.5 MB)

As far as total data transferred goes, these three imagines represent 82% of your entire site.

You should be able to greatly improve the situation by re-saving the images at a higher compression rate, either with the image editor you use on your own computer, or a plugin like https://wordpress.org/plugins/ewww-image-optimizer/

That’s much better, your site has gone down from 21 MB total size to only 7.76 MB:

https://gtmetrix.com/reports/www.concept8media.com.au/QjCMTcuf

https://www.webpagetest.org/result/170305_9B_W0H/

The only recommendation I can make beyond that is to just not have such an image heavy site. Your design relies heavily on images though, so if it were me, I’d leave it as-is now.

You’ve improved your site’s overall size and load time by almost 3x. I’d call that win. 🙂