You are terribly confused about the lighting companies you list.
Osram and philips (now Lumileds) are LED manufacturers that mostly ship the finished LEDs to China for assembly into lamp assemblies that you can screw into the socket.
Your list of UK lighting companies are a combination, according to their "about us" pages, are a combination of "distributors (stockists) of Italian, German etc" or the are "manufacturers" of lamps. Think about what it takes to be a manufacturer of a lamp. Connect plug to cord, connect cord to switch, connect rest of cord to bulb socket. How much "electrical engineering" does that take? Just for comparison, I built a lamp when I was 10-years-old (and my 8-year-old brother built one too).
They buy stock parts, set up a crude assembly line. Most of what they do is buy stock parts, maybe custom bend some tubing, cut and paint sheet metal, whatever. Mostly mechanical engineering but more likely a designer with some knack for manufacturing and business wits.
If you know so much about lighting, you should be able to easily put on your big boy pants and start your own lighting company to compete with the shops that don't employ engineers... unless an electrical engineering degree is not an important component to success of a lighting company.