Self clean I don't have a manual, so how do i 'self clean' this oven? Or am i just being stupid?

I have a B1422 oven and it doesn't have a self cleaning option. It does, however, have a clean assist option.
If you have a box with what looks like a teardrop in it then your oven has the same system.

What you do is pour a mix of water and washing up liquid into the base of the oven and switch the controller to the teardrop. The bottom element will then warm the liquid, and the resulting steam loosens the grime. You then use good old elbow grease to clean the oven.

Obviously you have access to the internet. Have you gone to the manufacturer's website? Most of them allow you to view the manuals on line. Are you sure that your oven is a self clean version? If it doesn't have a "clean" button, it's not a self cleaning oven. Here are the general guide lines. Remove the broiler pan and grid and anything else that may be in the oven. Soil on the front frame and outside the gasket must be cleaned by hand. Pres the CLEAN button. Four hours will show in the display. Change the time using the HOUR and MIN buttons. Press the START button. To stop the cycle, press CLEAR/OFF. Wipe up any ash witha damp cloth or sponge. If your oven has porcelain oven racks, grease the edges with a light coating of vegetable oil after the cleaning cycle. If you are not satisfied with the cleaning cycle, repeat it.