I have this in my bookmarks folder but I don't think we have ever used it! But you could give it a try. From what I understand it is aimed at schools but individuals can register for it -
https://www.startprofile.com/about-start/I home educated my daughter for the lower secondary years, and then she went to school from year 10 and has just finished year 11. She has receive absolutely no careers advice whatsoever - not even to help think about sixth form options, and from what I hear from friends with children at other schools this is fairly common. The schools have to buy in careers advice and the careers person i spoke to recently said most schools don't.
Both my children have changed their minds about what they wanted to do careers wise - although DS was set on physics from age 14 (and is now at uni studying it) DD has thought about animal care, conservation, prosthetics, carpentry, joining the Navy, and is currently thinking about studying neuroscience - all in the last 3 years. I think getting an overview of the types of jobs out there is fine at this stage.