This is a great stove. It doesn't come with a regulator, but this is good because if it did, it'd be a Campingaz regulator. Campingaz gas is extremely expensive in the UK. If you plan on UK-only camping, or short trips abroad where you won't get through more than one gas cylinder, opt for Calor Gas or Flogas instead. Of those two, Calor Gas is the more widely available.
The Calor Gas 4.5kg butane cylinders are probably the most appropriate for this stove. The refills are approximately £15. That gets you 4.5kg of gas. The equivalent Campingaz cylinder (the 907) contains only 2.7kg of gas, but costs £20.
You can also use propane gas with this stove if you like. You just need to ensure you use the correct regulator for whatever cylinder/gas you chose to use.
Before I bought this stove, I read that you can't use the grill and the gas rings at the same time. This is not the case - you can use all three at the same time if you want to. This being said, it says in the manual that this is not recommended.
Another comment made was that the gas rings are still fairly powerful even on the lowest setting. This is true, but to counter this,
slowly turn the knob past the highest setting (back towards the 'off' position) and you'll find that it's possible to maintain a very low, stable flame.
This gets four stars because the worm drive clips / Jubilee clips included are rubbish. I tightened them to the point where I felt the hose was secure, and they broke.
If you find this happens, you need M00 (m-zero-zero - not the cow noise) size replacement clips.