Another one here that says stick with it , concentrate on stretching your child sideways . The U.K. education is narrow and linear , that narrowness and a string of top grade qualifications at GCSE etc will be great And it will open doors BUT it won’t make him happier or more fulfilled or more resilient or better at his job .
Those skills come from what you put around a child’s formal education. The music, the team games , the Volunteering ( older obviously ) art , languages , cooking , the exposure to different types of people etc and the ability to try again when you fail the first time ( very important for bright children who are often too used to getting things right first time)
What he has at the moment is potential , it doesn’t matter how many digraphs he knows in the long run , it matters that he develops a love of reading which both enables him to access the higher levels of the curriculum when he heeds to and crucially gives him pleasure and broadens his mind .
The aim is to raise a well rounded, happy and socially responsible individual . I vividly remember being bored stupid by the academics at primary school ( I taught myself to read by about 3 , I am good at codes etc and it just seemed obvious . My mother thought I was memorising until she started giving me new books ! ) but the things I really gained were fabulous afternoons learning craft , playing the piano, singing ,making friends and playing tag etc. I only realised this by watching my own children and now they are almost grown I can see that the things which are really helping them In their adult lives are their resilience , their ability to pick themselves up and try again when things go wrong, their ability to work as a team , their hobbies which give them pleasure, their loyal and close friendships etc
You sound like you are a great mum by the way, don’t listen to the people darling on here. You will discover that you can talk at length about how good at football your child is but god forbid you say he’s good at academic subjects .