on the iphone they appear as a whole page on the iphone browser (that is, you can view the whole page - its little, but you can see it all). www.billybirddesigns.com
Abi, this site was actually exported using DW MX rather than version 7.
<meta name="Generator" content="Xara HTML filter v.5.0.0.939"/>

So if billybirddesigns appears fine on your iPhone then MX is unlikely the cause of the other sites not displaying as expected.
It could be another reason.

Opening in top left corner of iphone
And here are two that I created in WDP7 and then updated them in MX8, and then published, and on iphones they open up in the top left corner only www.australianpsychicclairvoyant.com and www.grandiscottages.com.au
Yes, these are MX generated sites
<meta name="Generator" content="Xara HTML filter v.5.0.0.939"/>

Note that the latest filter is
<meta name="Generator" content="Xara HTML filter v.5.0.0.947"/>
MX version update April 16th 2012

I'll see what else I can find out for you