"Clunk" when clutch pedal is released. Started after cambelt change.

I recently changed the cambelt kit on my Fiat Ducato. Took a while but managed it. Immediately after the belt change, I noticed a clunk when releasing the clutch pedal. I had to lower the engine to remove the engine guard so I assume I've caused some 'free-play' somewhere? All engine mounts are okay so I haven't damaged those.
The clunk happens when changing gears and releasing the clutch pedal (about half way) - so when the clutch plates engage and it takes up torque. There are no performance issues, no grinding gears, etc. I have noticed that the clunk does sometime happen when turning in reverse as well.
Any ideas? I have seen a lot of threads from people with similar 'clutch clunks' but haven't found an answer yet. No idea how I've caused it as I was working on the opposite end of the engine :/
Many thanks.

• #autos_vehicles
• #clutch
• #clunk
• #transmission