I have been playing Bobby Shafto for more years than I can remember in G on a descant (or soprano) recorder. It fits very nicely and the fingering is all straight forward.

If you have acquired a treble (or alto) recorder, you will not be able to play Bobby Shafto in G as the range is not right. The treble recorder, like most recorders has a range of two octaves and a tone comfortably and about two octaves and fifth if you are up to stopping the bell for some of the third octave notes, but the range runs from F to G" rather than from C to D" that you get with the descant. The tenor has a similar range to the descant but sounds an octave lower, its lowest note being middle C.

It is worth saying what make and model of recorder you are playing. BTW, modern plastic recorders from reputable makers are excellent instruments and fantastic value for money, especially the descants.