With a bit of research, I uncovered (on the ever reliable Wikipedia
I've seen the NTSC version go for quite a bit, but after an exhaustive search I've yet to find any indication as to how much the PAL version would be worth. The box is a little rough around the edges but the cartridge itself is in excellent condition and works fine.
I would be very thankful if anybody could tell me if this game is indeed, quite rare, along with a rough approximation of it's value. Also feel free to contact me if you're interested in buying.
Btw, here is the Wikipedia link.
Cheers!