Hi Paul
Here's the array I am sending to a GetGridMap soap call:

Array
(
    [GridMapRequest] => Array
        (
            [TaxonVersionKey] => NBNSYS0000005060
            [Resolution] => _10km
            [GridMapSettings] => Array
                (
                    [Width] => 340
                    [Height] => 478
                )

        )

)

This example takes about 4-5 seconds from my machine, and 5-6 seconds from a hosted server though that extra second is presumably nothing to do with the Gateway. Thanks for looking at it.

Just in case it helps someone....

In my dabblings with web-services I have used AJAX calls to selectively modify parts of the web-page after loading. Using selectors on the web-page users can request different info from the gateway via an XMLHttpRequest, after which various "div"s are re-written using the data returned.  I've only used the synchronous form of XMLHttpRequest so far (below), but truly background requests should be possible by selecting asynchronous operation. The web-page is only loaded just the once.

If it helps anyone to get started, this is the key AJAX bit. The url is the address of the php containing the request, which in turn uses soap...

function loadXMLDoc(url)
  {
    if (window.XMLHttpRequest)
        {// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
        xmlhttp.open("GET",url,false);
        xmlhttp.send(null);
        }
    else
        {// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        xmlhttp.open("GET",url,false);
        xmlhttp.send(); // Do not send null for ActiveX
        }
    return xmlhttp.responseXML;
    }

It doesn't help with gateway response time of course, but at least the user has the rest of the web-page to read while waiting.

Regards, Keith