I converted to a UK licence about 11 years ago. I'm sure things have changed, but back then it was just a matter of posting the existing one in, and they posted the new one and the old one back to me. No checks were done at all.
I'm not sure if your question about getting a UK licence was just a hypothetical question because you would still have to get a CH licence after 1 year anyway.
Just a few pointers for driving in CH:
1. If you have a "bakkie" you can't put 50 labourers / gardeners on the back of it and drive around
2. Overtaking on the inside is not only illegal and dangerous, but it will get you flashed by the car behind
3. You can't drive at 100kph through residential areas just because you feel like it.
4. Your car has to be roadworthy
I spent 6 months in Cape Town last year, so I know what I'm talking about.. You'll probably find the SVA a very efficient and non-bureaucratic place in comparison
By the way - the fact that you have to do a "control drive" is only because your licence was issued in a third-world country. It used to be that the list of "in" and "out" countries at the SVA was a bit different, but these days it looks a bit like first world countries are in, and others are out. If you were converting a UK licence to CH it would be done without a test.
Mind you, USA is listed as an "in" country and I know many Americans who can't drive manual transmissions (which they curiously call "stick") and whose test consisted of driving around in a car park...(or sometimes, not at all!) So go figure. Also - I'm sure the list of which countries are in or out varies between cantons, as well the requirements!
If you can drive you probably don't want to spend too much money on lessons, but then again if you don't even own a car it might be your only practice. In which case.. check out www.mobility.ch
Mark