Competency Assesment - What to expect

I have an interview on Wednesday with the BBC in Cardiff for a Camera Assistant position. Although it's not technically an interview it's been billed as a 45 minute competency test. I have a vague idea as to what this might entail i.e. assembling kit in front of the three person panel. Am I right in thinking this?

Does anybody have any insight into this they can pass on? Has anybody been experienced this?

Any advice is much appreciated.