Mr D
The reading from the screening device is only relevent is that it provides evidence to arrest, which has to be lawful, in order for the blood test to be admissable. The evidence will also have also said it was required by a Police Officer in uniform, again for the same reasons, it has to be administered by a Constable in uniform, or again, the requirement will not be lawful. Again, it is admissable evidence, but only relevent in establishing the lawful requirement of blood.
Wheelbarrow
When you think about it, airline pilots have a status of professional, and being in a position of great responsibility. As such a breach of law, which is safety related is going to be taken seriously. Those are strong aggrivating factors. What is there mitigation wise? Not much really, again, your position acts against you. Same as a Police officer who abuses his position can expect prison if convicted, and certainly a higher sentence than a member pf the public.