Worriedmummybekind
Having a week off does impact on progress and learning.
I'm not cramming to the test. I'm teaching a well designed curriculum where lots of thought and consideration has gone into the order we teach things, when we do assessments etc.
If a child misses a week then they'll come back having missed a section of knowledge and skills which they then have to play catch up. Playing catch up is not the same as being taught the new skills and content in a logically structured lesson with models, scaffolds etc. We don't pluck topics out of thin air and then do a few activities to fill the day.
To say schools who as a week off are cramming to tests shows a total lack of understanding about what goes into teaching.
I'd happily allow a parent to take their child out for a week at ks3, as long as they don't expect me to do intervention and provide catch up for material they chose to miss. I also don't want them calling me up complaining if on that half term' s report their child is behind.