Thanks for all your comments,
spent today looking at bikes in Halfords, Decathlon, Toys R us, Evans and a LBS.
Originally thought I could get her a 20″ bike – something like the Giant Areva that Wiggle have on offer, however now I think that may be too big, probably a 16 or 18″ wheel bike would be better, however hard to tell as they seem to go on wheel size rather than frame size.
Motox2k – How did your 5yr old get on with a 20″ hotrock, my daughter is 115cm and the 20″ Carrera Luna I looked at in Halfords seemed a bit too big.
The 16/18″ bikes don’t appear to have gears so a 20″ would be preferable, but I don’t want to get her something too big that might put her off.