Are they going to find anything?
Well, as they say, it is voluntary. You don't have to agree therefore. Obviously teh refusal to do so may well affect their attitude towards you and their willingness to spend resources upon you. Generally that is a bad thing.
I wouldn't suggest aggravating them if I were you.
Can I clarify for you?
Ok. So what is your question?
No, because the DPA doesn't apply as this is the detection of crime.
It is as I've said above.