So, if you type http://download.slingmedia.com/spcd/gtv/index.html as a web address in Chrome to get to your slingbox directory on the sony box, you still can't access It? My understanding is the spotlight app in google tv is nothing more than a web link that runs flash through chrome. If the sling app isn't available on a U.K sony google tv box, how about accessing it directly through the web browser?
From there, you can add it as an app bookmark allowing you to customize it as one of your home items on your main menu. That's how I connect to my slingbox which is nothing more than a slingplayer icon weblink accessed from the googletv home button.
yes that did work, though it means I need to depend on a website to be available to watch the sling, which is now converting me to go for two x Vulkano Lava's at this point, unless I got it wrong.
I have yet to purchase the Sling 500, which is what I was going to do (awating for it to arrive in the UK), but if there is not an App for the GTV, so if the Sling website is done, then this is probably not the right route for me.