1. Should I get the Andis AGC twin clippers (black colour) or Andis super speed clippers (also twin speed, burgandy colour and about £6 more) The only difference (I think) is the strokes per second??? 
Either one will do, the super speeds are made for grooming shops where they are doing a variety of breeds and coats, the top speed on the supers are for getting through very thick or matted coats. (That high speed heats up the blades pretty quickly too
) The twins should be perfectly fine for a normal or even thick cocker coat
2. Can you clip all the way down and around paws (his paws are creating so much mess and wet at the moment as so long) but keep very slighly longer at the back of his legs? This is the look my groomer does for me. How would I achieve that look?
Yes, you can. I take the clippers straight down the front of the leg, on the sides I hold the leg out in front of the dog (like "shaking hands" or "give me paw") and gently feather the clipper down off the side. Takes practice
You will have to finish the feet with scissors and thinning shears.
3. I like to keep a short skirt. I really don't want the Shaun the sheep look. What do I do about that bit, so I use another type of blade or scissors? I'm a bit wary of pointing sharp scissors at him!
You can use a #7 blade to skin the ends off, this one takes practice too but gives a nice natural finish once you get the hang of it. If you use scissors, be sure to cup your free hand over his penis so you don't have any accidents
4. I like to keep the ends of his ears as short as possible. Can I clip here?
Depends. If you are leaving the feathering on the outside of the ear it would look better if you scissor or use thinning shears on the ends. Otherwise you can just clip it all off if you like
5. It grows back....right! 
Oh yes, it does!
