When I was that age I struggled to know what I wanted to do when I was older because I had no experience of the world of work, my only experience was school and arranged around school subjects.
How many adults do you know with jobs? Could you arrange for her to visit as many companies/as many of those adults at work as possible, or if visiting is tricky, get them to send through info, "a day in my life" kind of thing. I sort of knew about jobs which directly related to subjects I liked, so designer/illustrator, and jobs which I'd come across in the world like teacher/doctor/chef/postman/etc but things like a HR department, project management, quality control, research and development of specific things - those things were totally missing from my understanding of work, and in hindsight it would have been really useful to know about them. I was approaching work from the standpoint of what skills I have and what type of work would suit me, without really knowing what jobs exist. Instead you can try approaching from an interest point of view - what's her favourite brand or product, does she have a hobby?
Let's say that she loves a specific computer game - there are hundreds of jobs involved in producing a computer game, from the conceptualising to the art to the coding to the testing to the engagement with the community to the marketing to the events management to the translation etc etc - loads and loads of varied roles. Or if she likes rock climbing - there will be hundreds of roles associated with that, from a trainer to a competitive climber to somebody making and designing new types of ropes and harness, safety testing the ropes and harnesses, making/designing the clothing, mapping out routes, running an indoor hall, designing, building, repairing indoor walls.
Does she like French? What about an exchange year in a French school or even Canada? That's the norm across Europe, it just doesn't seem to be done in the UK. Despite the name there is no requirement to have a foreign student in exchange. It might be expensive if done through a private company, though if you are on a low income and she is very good at French she might qualify for a scholarship.
I agree with looking at local colleges as they often offer much more of a range of courses than the usual A levels - there are courses in travel and tourism, animal sciences, so many things. Colleges often have great careers advisers as well. Get her to give her local college a call and go in and see someone.