My dh reckons it's all the mumsnetters causing havoc by trying to post all at the same time, can't think why, it's not as if any of us have anything better to do!
When this has happened before, I google "mumsnet" and it instantaneously comes up with the site and is all working perfectly. I came off, and tried to get on again through normal channels just to check, but still no joy (but googling still OK).