I don't really know even though I have had a mac. Wanted to try and help anyway though... Could it be something to do with your firewall or a pop up blocker? Just guessing. Hope someone who knows what they're on about comes along shortly.
It is a new machine - it doesn't come up with an error message, it just won't load and eventually times out. It's really odd, I can get on to Waitrose for example but it won't link through to John Lewis. DH is playing with the settings now - I know it's not the JL website as I've just been on through my PC.
Themaster.. that's not right. There is something wrong with your dns lookup.
You should see this result for www.johnlewis.com:
www.johnlewis.com. 27923 IN CNAME johnlewis.com.
and for johnlewis.com:
johnlewis.com. 27818 IN A 22.214.171.124 johnlewis.com. 28578 IN MX 50 relay0.johnlewis.co.uk. johnlewis.com. 28578 IN MX 50 relay2.johnlewis.co.uk. johnlewis.com. 28578 IN MX 80 mx.johnlewis.com. johnlewis.com. 28578 IN NS ns0.johnlewis.co.uk. johnlewis.com. 28578 IN NS euro-ns2.cw.net. johnlewis.com. 28578 IN NS euro-ns1.cw.net. johnlewis.com. 28578 IN NS ns1.johnlewis.co.uk.