Hi Colin,
Welcome! I am from Stevenage and only just joined the other week

We're quite lucky as the riverside garden center between Hatfield and Hertford is the largest re-seller of Webber. I go there all the time! I call it BBQ World as it is our dream when you see how much stuff they have!
There are a few schools of thought for your kettle. Weber suggest placing your coals on either side creating a in direct heat channel in the centre. This will allow the air to flow round similar to your oven at home. Hence why we use a lid

I have found there is not enough grill room to do this and split half/half well more 70/30. Some people place foil I'm between to protect the meat. I even saw something crazy called a smokenator.
The trick is to learn how to control the temperature. The trick is to use half a chimly unlit and a few bickets lit like 8-12. This will differ if you buy weber or tesco coals etc. the lit coals will slowly burn the unlit. Obviously less temp. Less lit coals. I found this easier than messing about with the vents.
Also look at the different types of wood against the food your cooking and when to wrap in foil. Some people love a smokey hickory taste and others do not.
Hope that helps!
Talk soon
Paul