It turned out to be only me and Claire in work the next day... oh well, all the more for us!!
Mix the eggs, one at a time, in to the chocolate and butter mixture. Then carefully fold the flour mixture into the chocolate mixture. Don't over mix this or it will become too cakey.
Bake in a greased baking tray lined with greaseproof paper (also greased!) at 270c for 20 mins (or a little less if you oven is hot!) don't over cook, the brownies should be gooey in the middle.
Take out of the oven and allow to cool for as long as you can bear before cutting into squares and scoffing!