It's called:
Microsoft .NET Framework 2.0-KB2656352_20120115_170616703-Msi0.txt and is around 13Mb.
I only discovered it when CCleaner had difficulty in deleting it.
So has anybody got any idea what it is (I know it's to do with Windows updates) and whether it can be deleted?
I know this is my first post for ages, but I do look in about every other day, honest.