stuck in reverse

hello,im new to this club but need some advice.my wifes car-1983 golf gti is stuck in reverse and its probably my fault….let me explain.
we bought it recently(very cheap from a friend),when we got it ,speedo cable wasnt fitted,so i thought i would fit it and did so but the orange plastic worm gear didnt sit in the little hole inside the box and came off the end of the cable and into the box.i got a new one and thought that the old one being plastic would just get mashed up by the gears…..wrong!!!its obviously wedged between gears-hence being stuck in reverse!right so i thought i would take the gearbox out…….sounds easy when you say it!!!…..everything is off or unbolted except one bolt on drivers side drive shaft…which will not budge….even tried banging a socket on it,but its not having it.
has anyone else had this problem and if so how did you get it off?also has anyone in kent area got a spare 5 speed box for sale-incase i cant get the plastic bit out of the old one.thanks in advance sean ops:

http://www.vwgolfmk1.o…=435700&highlight=#435700

http://www.vwgolfmk1.o…orums&file=viewforum&f=14

does it still move if only backwards