Gearbox woes

[bashbarnard]

been driving my lovely motor around now and coverd a few thousand miles since ive had a play and its perfect. Jumped in other halfs 306 today and the gear change is horrible and notchy. It did have a clutch done on it before it came to be in our ownership. Reasnably light clutch pedal still. Its like trying to stir a wooden spoon in a bucket of gravel. Now ive got a spare box but before I jump in I was going to change box oil. Anything else thats common on these? Linkage issues? Anyone had a similar issue??