By 'waterproofing capabilities' I suspect you are referring to beading, and 'polish' I suspect you mean a waxing, rather than abrasive polishing most likely using a machine ?
So you really want a clay bar kit, a non-abrasive pre-wax cleanser to apply by hand (ensure the wax sticks, adds oils to paint, cleans the surface ) and a wax.
I'd therefore recommend Race Glaze Signature PreWax Cleanser, 250ml £15, and 55 wax. The shine will blow your pants off. Its all dead easy to use, no abrasives nor fillers, will last 6 months on cars kept outside. And its exactly what I will be doing on Saturday, if the weather is good, after collecting our new (to us) CLK tomorrow.
I honestly cant recommend AutoGlym products, they are old hat and things have moved on. The SRP is chalky, dusty and leaves white marks all over any black trim, and lasts 2-3 weeks. Thats why you need wax.
Vertar clay is well regarded and low cost/good value, you can get the Race Glaze stuff off there too:
Car Care, Car Covers