As mentioned you need a tap for the top of the 907 cylinder, available in any camping shop. It is highly probable your existing high pressure butane hose will fit the cylinder. The only issue that sometimes occurs is that as the 907 is shorter than the Calor cylinder, the hose may not be long enough to reach, if the regulator is fitted high. In this case a longer hose is available, again at camping shops. You may also have to raise the 907 cylinder in the gas locker in order to get the securing strap to fit correctly. I used a small block of wood under neath. I now have a twin set up with 1 Calor and 1 Camping Gaz connected through a gauge. Therefore if by any chance a hose did fail, I have a back up until I get a replacement.
The other good thing is it is easy to unscrew the 907 to use with the BBQ, but of course you need a normal 28 mb regulator and hose to fit to the BBQ. I appeciate as newbies this may seem complicated but most of us have 'inherited' various regulators over the years and can fit virtually everything nowadays.
You can get your 1st cylinder anywhere in UK/Europe and exchange it anywhere, that is the beauty of them. It is slightly more expensive, but negligible for the convenience.
Others have mentioned the BP cylinder. Yes, it is a lightweight cylinder but has nowhere near the availability of Camping Gaz, especially if you are in a quiet area. It is also propane which is better if you are planning winter caravanning. If only summer, then butane is probably better but again people have different opinions.