Advice re transport and smoking

For issues specific to caring for someone with learning disabilities
It’s been some time since I posted and wanted advice so here goes.
My daughter has multiple complex needs and is transported daily to her placement. Chest problems especially.
I have been able to smell cigarette smoke I her taxi and confronted the driver and escort who (eventually) admitted that they have smoked in the vehicle, although not when she has been in it.
I explained that it was against the law and they apologised and said it wouldn’t happen again, they now sometimes stand at the bottom of my drive smoking before they get in the taxi to transport her!
Just as bad in my book!
My problem is that they say they don’t smoke in the vehicle and then this evening as they were pulling away I saw the escort taking out her packet of cigarettes!
I know I should report them but I wanted to see if I could gather evidence first, sounds sneaky I know but I feel I “Need to prove my case”
I have been looking to see if there are any smoke detecting patches etc I could use but can’t find anything.
Perhaps I should just air my concerns to the council and get it over with but I know they don’t have any other staff trained for my daughters complex needs on the other hand I am not willing to put my daughters health at any more risk.
Hi DebM.

Perhaps I should just air my concerns to the council and get it over with.

Short of that , what would be the alternative ?

The driver and escort are in breach ... allegedly ... down to the LA to sort out.
I've just Googled "Smoking in a taxi", it's apparently banned WHETHER OR NOT it is currently being hired.

They are supposed to be there to care for your daughter, not put her health at risk.

I think you should report them immediately to the taxi licensing authority, usually your local council, the one that handles Council Tax.

I had to do this for one of my son's "taxi" drivers taking him to school. I knew it wasn't a proper taxi as it didn't have a licensing plate on the back. In the case of an accident, my son probably wouldn't have been covered by the car insurance.

Don't delay, just bite the bullet and do it.
Thanks for the reply guys, as I said, I wondered whether I should gather evidence first, I’ll be making some calls in the morning.
If you contact the person responsible for issuing the Hackney Carriage Licences at the council, I'm sure he will take it seriously, and do a "spot check". All he has to do is sit in the car and take a breath, because as you know the smell of smoke lingers.
A couple of photos would help. No need for a long log of incidents.