I own the .co.uk for my site so could in theory move it from the .net using a 301. However, I do not have sufficient faith in Google's handling of 301's to even consider moving domains. I have hundreds of backlinks pointing to the .net.
The site has always shown up within the UK until now, and is physically hosted in the UK. This particular problem only currently affects the homepage, none of the other pages are affected. For this reason I believe it to be a Googlebug and I am confident that it will be fixed shortly. Fingers crossed ;-)
I also don't trust 301 being handled correctly. I wouldn't trust google to wash its hands after going to the toilet at the moment!
It may be a bug but it seems to be a recurring one. My site suffered all August and came back for a week or so and is now gone again. So even if you do recover don't expect that you are out of the woods.