I'm not sure what you are referring to as the "provisional" but I can answer your other questions. **Edit: ok I know what you meant now by the "provisional." Same advice. She has to learn that 72 more hours means 72 more hours.**
First, as a parent, please do not look at this as "getting her off." She needs to learn a hard lesson here because while breaking the law now is relatively minor, she needs to learn that the world is far less forgiving as she turns 18. I hope you are on the same page with me there. I personally might take her license for the remaining 4 months until she turns 18.
As for the legal question, hire an attorney. It will be fairly inexpensive (something under $500). MAKE HER PAY FOR IT. Again if she does not learn there are painful consequences now she will later and they won't be as easy to deal with. Your attorney should be able to negotiate two tickets into one (Especially if you tell the Solicitor that you have taken matters into your own hands by taking her license for a period and making her pay for her own attorney).
No one wants serious LEGAL consequences for a 17 year old. What they do want is to see that the 17 year old has or will learn her lesson from the consequences that happen. If a Judge and or Solicitor sees the parent is well grounded and understands how very serious this is, He/she is likely to work with you. If they have the idea that you are trying to "get her out of consequences" they will rightly try harder to teach her a lesson.
Overall there will be consequences. If you take my advice they should not follow her for very long (depending on the law there.) Good luck, I'm very glad she didn't end up with a dead friend or dead herself because of what she did. We all have done it, but its still very dangerous and wrong.
