Rob found mathspace:

• Moderately improves attainment“In an end of term year group test, set 4 matched the attainment of set 3.”
• Significantly improves teaching efficiency and productivity“Significantly less time spent preparing lessons and resources, and on marking student work. Less time answering simple queries in class, more time spent helping those who are struggling.”
• Significantly reduces teacher workload“I would typically spend 2 hours per week planning and producing resources for lessons and homework. This is typically less than 20 minutes now.”
• Slightly improves teacher knowledge and skills
• Moderately provides school data