It sounds as if they didn't tighten the nuts securing the wiper motors to the headlights. BTW, the only change in switching from US to Euro wiring for me was rearranging the wiring pins into a 6 socket Euro connector. The H4 and 9004 headlight bulb are still 55 watts, the Fog is still an H3 at 55 watts, all you added was an 8 watt city bulb. No big current drain there! Did they install 85 or 100 watt bulbs? (The British sites state anything over 55 is illegal on there roads as well as over here.)
Check the securing nuts on the motors if it is parking and moving to different patterns every time. If the nuts are loose, I would ask for my money back on the labor, and ask that they explain, using Ohms law, where the extra watts came from that required additional wiring!
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E