Hello! personally i think the andis 2 speed are a great clipper, i work for a grooming company and they would be one of the best sellers for pro groomers and pet owners alike, they are strong enough to clip through thick hair and are a nice shape to hold, plus they come with a free no.10 blade which is good for the indside of ears, stomach etc. Andis would be better than argos/pet store clippers as they really arnt up to much, not powerful enough in my opinon nor are they sharp enough to give a good finish!
generally with grooming tables it's always handy to have a control post/arm, just so your dog cant jump off the table and hurt themselves, also, it gives you a bit more freedom as you dont have to worry about holding the dog still while clipping! the seller will usually say what maximum weight the table will hold but for a spaniel you shouldnt have too many problems getting one to suit!
and as far as i kno in england a lot of colleges and even some grooming salons offer short courses for grooming so hopefully you should be able to find a course to suit, may be worth your while calling any local groomers and colleges to see if they offer a course!