Can someone talk me through the basic process for getting an extension? 
I know it's within permitted development for my area (Denbighshire) of not more than 4m long, it doesn't cover over 50% of my plot, it's on the back not the front, and something about eaves height.
I've got a trusted builder, long time friend, excellent reviews.
What I want is a rectangle attached to kitchen which is one half of the back of my square 20 year old house, with a lantern roof. Nothing elaborate.
He's come round today to have a look, and has given us some questions to think about and will come back on Thursday to measure up and get us a quote by the end of next week.
All sounds great... but what are building regs? Do I need an architect? Do I write to the planners?