Could this be the same thing as OP has noticed - http://www.a1-forum.co.uk/a1forum/viewtopic.php?f=7&t=5398&sid=5ce2373f33ad0a85c82e3ffc8880ae3e?

 

Similar setup with the 1.6 TDI 105 and 5-speed manual 'box 

My fabia does this. I just change down a gear or dip the clutch as the revs drop.

 

It took a bit of getting used to when i first got the car, especially due to how long the gearing is. I can't complain though, as the long gearing also results in good mpg and a relaxing just over 2000 rpm on the motorway.

 

I find I need to be doing over 30mph on the speedo to be comfortably in 4th gear, and over 50mph on the speedo for fifth. I can happily tootle round town without ever changing above 3rd depending on the roads/traffic. It feels as though it could do with an extra cog in there somewhere on occasion. I'm by no means an advanced driver though. I imagine the 5 speed box on the 1.6 CR is similar?