Difficult downshift to Gear 2 or 1

[fuvureju]

Hi all

when I am in gear 3 or 4 and try to downshift to gear 2 or 1 occasionally the gear lever wont go across from 3/4 line into the 1/2 line.
I have a 1.9TD 408 mk1 5 gear transmission (think BE3)
The clutch feels fine and the gear shift just a little notchy on moving the gear stick
Does anyone have any ideas what may be causing the problem?

thanks