Rumncoke wrote:

"As far as I can see the fingering is exactly the same on all recorders"

The fingering shapes are the same but the notes are different. Some recorders are in C and some are in F. This means that, for example, the fingering which gives you a C on a descant recorder will play F on a treble. To play C on a treble you use the same fingering which would give you G on a descant.

You can play a tune on any size of recorder using the same fingering, but it will play in different keys.

The Dolmetsch site is at http://www.dolmetsch.com and includes fingering charts for F and C recorders