Echo Hasbeen's thoughts/recommendations.
No point in over thinking the solution trying to find an at home alternative that may/may not prove acceptable. There are people out there that do this sort of thing for a living and for a reasonable price (unless they are not interested). They are very good at their trade and can return a damaged item to near as original. Plastic welding is used in many industries - bumpers and motorcycle fairings as discussed, also quite common practice in the travel space with repairs to plastic luggage typically available within reasonable range of many passenger based airports. Check out Mr Google, Yellow pages or ask around.
The weld is heat based, somewhat similar to the metal equivalent and can be supplemented by suitably coloured filler rod if necessary followed by clean, prep and paint for like new result. Rgds DM
