We did find some stuff about summer schools and courses but every one I opened then said they were only for people who would be the first generation of their family to go to university so she doesn't qualify.
Try googling "university summer school engineering" and you will find quite a few e.g.
www.taster.ecs.soton.ac.uk
which are open to year 12 students, regardless of family background. For at least some there would be mild positive discrimination towards women i.e. given a male and a female applicant with similar grades and one place left, the place would be given to the woman.
There are also some initiatives specially targeted at women. Partial list available at
www.wes.org.uk/content/engineering-summer-schools
but googling "girls engineering summer school" should bring you up more.