I have just bought a 1988 Eriba Puck with an empty 4.5 kg Butane cylinder in the locker. I have a number of partly full 6 kg Propane cylinders from previous caravans / Motorhomes. The 6 kg cylinder also seems to be more easily available than the smaller cylinders. There is no issue with modifying the locker and fitting the larger 6 kg gas cylinder?