Pulled away from junction in 1st went for 2nd and the gearknob sprung back into the neutral position. Then it would not select any gear everything felt sloppy and springy and I found a gear in the 4th position but it was 2nd gear. Got it Home and have replaced the parts suggested by my local Seat parts which mean I can now cycle through all gears except 6th which still springs back out. Whilst the car is off it is fine, as soon as the car is back on it can’t select any gears again. Question- big gearbox problems or have I done something wrong?