Question - guggling clutch!

[bakerlonglegs]

This seems a really daft question (even as I type it) but when I was cleaning the bike on Sunday I noticed that the clutch fluid reservoir makes a guggling sound when you squeeze and release the lever. Now I normally wouldn't worry but after picking it up from a service recently there was a pool of clutch fluid in the handguard. No new fluid leaks since then, and the level looks OK, but does anyone else's, er, make a noise?
Any help appreciated.....
BLL

 

[Deleted account W]

This sounds very odd

 

[Steptoe]

You may have a frog residing in your handguard

 

[Mouse]

Is it the rubber boot on the master cylinder creaking?

 

[Little legs]

Mine did make a noise but more like a squeek than a guggling