These are some of the programming tasks that I give to my GCSE students to practise their skills once they have mastered the basics. As it tends to suggest a solution, I rarely use PRIMM at this stage - I discuss possible solutions and techniques at the start of the lesson and recap things as necessary. I would encourage the more confident students to come up with their own solutions, possibly using techniques such as recursion and object-oriented programming.
Discussion before the task would include questions such as:
I have not included tasks from the OCR Coding Challenges, but I have included two from Advent of Code so that students don't need to log in to get the data files. I came up with a lot of these ideas myself, but I can't remember where some of them came from, so please let me know if any of them is yours and I'll credit you. Some solutions can be found on the programming examples page.