Crunchy Gearbox/Clutch

[Berlingo_1999]

My Berlingo Van has had a problem with the clutch/gearbox for the last 6 months. To begin with it wasnt that bad but has slowly got worse and I need to get it sorted out asap. If I put it into 1st gear really slowly from neutral, or if I put it into 2nd gear from neutral and then move it straight from 2nd gear to 1st it doesnt make a crunching noise, but it if I put it into 1st gear as you would with a motor that was running correctly it makes a terrible sound. Is this a clutch or gearbox problem or is it impossible to tell without looking at it, feedback appreciated.