Ds is 5y 8m and in year 1. He has gdd, we've been told it's mild. The HV and preschool used to do quite detailed assessments and make it really clear how far behind he was. School were a lot more vague about it although we have older dc as well so we have a fair idea about how far behind he is.
Today we had his review meeting and we got his phonics screening test results. They do it a few times before the official test at the end of the year. So far he has mostly scored 0 but this week he has scored 3. Our older 3 dc scored top marks or nearly. This sounds like more than mild gdd to me.