He hasn't been charged yet, arrested on suspicion of.
Roadside machines are not suitable for evidence as they are not calibrated. It is only the machines at the station that can provide evidential samples.
If he is guilty then he should face the same punishment as everyone else, except he won't. He may well gain more public sympathy than others in the same position, but no doubt he will continue to be hounded by the tabloid press as he has been for the past 9 months or so.
I lost a relative to a drink driver, I have zero sympathy. I have also been very close to mental illness and addiction.
Being hounded in the way he has whilst trying to recover must have put an intolerable pressure on him. Instead of having time to focus on his recovery, he has been followed and photographed wherever he has been, whilst also in the midst of a marriage breakdown. I would imagine, regardless of public statements, that there was also a great pressure to return to work as well.
He does not deserve excuses to be made for him, but if he is struggling rather than this being a moment of monumental stupidity then I hope he is given the time and space he needs.