[ubuntu-uk] Live usb question

[Barry Titterton]

I recently created a persistent live USB for the first time. It worked
perfectly but there is one aspect of its behaviour that I do not
understand:

I used a 4Gb stick. After creating the stick in 10.10 using the built-in
disk/USB creator, I added Restricted Extras as well as creating a couple
of files to test that the persistence worked, which it did. However, at
this point I ran Update Manager which downloaded and installed approx
210Mb of updates. Before the update I had 2.7Gb of free space, but after
updating this had shrunk to only 1.5Gb. I thought that I had done
something wrong so I formatted the stick and repeated the whole
installation, but got exactly the same result.

Can any of the members explain it? Is this normal behaviour for a live
USB?
Is there an easy way to get any of this space back, or should I avoid
running Update Manager?

Barry T