FMSP isn’t all about A level Further Maths. They have some great GCSE resources too.
This page contains some superb resources for problem solving and group work with some very helpful discussion prompts and worked solutions for each question.
These look like nice resources for introducing group work, as each member of the group has “their” cards but they work collaboratively to complete the task.
Also, this post from Number Loving has some good suggestions.
mho maths 