If I remember correctlty, Calor supply both propane (red cylinders) and butane (blue cylinders). The also supply the green cylinders especially for BBQ's as they have a special fitting in place of the normal regulator, but I can't remember if these are filled with propane or butane. You definately can not use butane instead of propane (or vice versa), but must use the gas it was designed for.
First off, the two types of gas are propane and butane. Calor are just the company who supply it.
Can't remember which way round it was, but my barbie was supposed to use one type but I use the other. I had an old gas bottle laying around so didn't want to buy a new one. The guy at the gas shop said it would be fine but I needed to fit a new regulator on the barbie - the two different types of gas have different fittings so you can't switch them by mistake. I've been using it for years with no problems.
Propane burns at a higher temperature than butane so for sensistive equipment it would make a difference, but for barbies either is fine.
Calor is a company who bottle both propane gas, red cylinders and butane gas, blue cylinders amongst many other gases.
You cannot fit a propane regulator to a butane bottle and vice versa. Your barbie will work with either gas, although some people say that propane burns hotter.
Propane continues to "gas off" at a much lower temperature than butane, which probably will not matter in a gas barbie unless you use it in winter.