I have just bought a second hand Punto 1.2 8v for my son, a fairly sensible driver. It will now not go into gear, the gear stick has free movement forward and back but will not go side to side. It is possible to select a gear under the bonnet. Both cables look to be properly connected at gearbox end and underneath selector box. Any suggestions as to likely cause and cost of repair? Suspect problem at gear knob end. I am no mechanic, will need to go to garage.