ford.hard to get into 2nd+reverse

hi all

i've got a new shape ford transit 2001,front wheel drive,2litre turb diesel.i've owned for 18 months

for the last 2 weeks i some times find it hard to get into 2nd and reverse gears,..i.e

clutch down..shift to reverse..clutch out..gearlever pops out of reverse

it sought of seems that if the lever could move a further 2mm,then it would stay in gear.i've taken rubber floor gater to check for free movements.

it also happens when i change from 1st to 2nd..i some times have try 2 or 3 times

my configuration of gears is:

its done 63.000 miles one origonal cluth

any ideas

thanks rday