The FOR SALE section on this forum site is free of charge, so it might be an idea to start here. Of course I think I'd be right in saying that most of the people who are members here probably model various Australian prototypes, but there are definitely at least some modellers of European prototype, so it'd be worth a try.
The other popular avenue is ebay....but be prepared for the not-insignificant fee structure!!! (the words: "bloody rip-off" spring to mind, especially with the additional cost of Paypal's commission).
Another avenue might be a hobby shop....some used to take models on consignment, but in my experience they are only interested in the high end of the market (up around $1,000- per model....eg: brass locos), and probably not interested in European models at all.
Finally, you may be able to sell the lot in one hit to one of those dealers you often see at the various exhibitions. Once again, they won't be rushing to offer you oodles of the folding stuff.....which is fair enough in my book, as they may have to sit on it for many months or years, so they are taking a calculated risk that they will eventually sell your models for more than they paid you.