First of all, if you want the definitive figures for your car, ask Skoda for an EU Certificate of Conformity. Legally, they are obliged to issue ONE, free, to the first purchaser of the vehicle. They don't look like much (just a single sheet of A4 with lots of data printed on them), but they're a valuable legal document. They're unique to each vehicle, so there won't be any messing around with weight ranges, it will simply tell you exactly what your car can legally tow, braked or unbraked, including nose weight. Look around Field 18. The certificate will have your car's 17 character VIN on it.
Secondly, towbar prep is, as has been said, various cooling system upgrades, plus the necessary interface for the wiring. Lots of people (me included, have NOT had towbar prep and tow things. There is no legal problem with doing so, but there may be warranty problems if you cook your engine whilst towing. Just watch the temperature. Most of the time, in the UK, unless you're towing the maximum weight in the middle of summer, up a steep hill, you'll be fine.
Thirdly, we had ours done by PF Jones in Manchester and we're happy with it. Make sure you go for "coded" electrics.