Imperial College, based in West London with campuses in South Kensington (where the computer science department is), White City and Hammersmith, can offer your (geographically-adjacent) school one of its computing students.
You don’t have to be offering computing on your curriculum, the student can help with after-school (or lunchtime) code clubs and that sort of thing. There’s a video on the page which gives an overview of the programme which promises light-touch admin for busy teachers :)
The next placements will begin in January 2023.
“The Department of Computing places upper-level undergraduate students within London-based primary, secondary and sixth-form schools as part of their undergraduate module ‘Communicating Computer Science in Schools’ for approximately 6-8 weeks (around 1-3 hours per week).
We are looking for more schools to host our students during the Spring term (school terms three and four, January – April). Please complete this short survey to express an interest, after which the module coordinator will be in touch.”