Gearchange Clunk

My Octavia 2 Td manual has developed a clunk changing from 5 th to 4 th. Sounds and feels like something "hanging on" and then letting go and causing a clunk. It only happens about 1 time in every 3 or 4 changes and doesn't sound like anything is grinding crashing tearing or so on just a clunk

It also happens more often if I flick the lever into neutral before pulling back into 4 th.

If I firrmly move the lever with a grip as it were on the lever for the whole movement it happpens much less often.

Car has done 1000 miles.

Any ideas anyone?

Anyone had it or got it ?

HopeImRight (I really do). :(