Hooray! Finally broke the block yesterday. I tried that old trick 'write as many prompts as you can into a flash' and it worked because 824 words later and I had a finished flash about 2 women swimming the English channel. It wasn't great and only scored in the mid-late nineties and (as with a lot of my stories/flashes) there were credibility issues, but I did it - I wrote something with a beginning, middle and end. It's only taken, oh about 3 weeks to get here.
Now please excuse me while I do a little happy dance.