Sorry, Mark! - I got side-tracked again (to many threads, not enough eyes!)
I get the same results as you do (I should have checked it first!), and thinking about it, the file we need isn't there, anyhow!
The trick is to find the right ones, because the filename doesn't include the KB number - it's part of the XML code inside each mum file that we've uncovered.
I'm going to have to play with this - and it'll take some time, so that may be your best option.
I'm fumbling my way around to try and find a quick solution - the only one that springs to mind is a repair install