NFER test results

[GrumpyInsomniac]

My 10 year old has come home brandishing an envelope that gives test results in English and Maths that apparently give him an NFER band D, whatever that means, that we have to quote when applying for secondary - this apparently relates to some tests they did in Y5.

Since the school told us nothing about the tests, and have given no indication of what the levels mean, I have no clue how to interpret the results. He's usually quite bright, so I'm assuming D is not the bottom, but if I'm wrong and it is, presumably my son struggles with tests. Either way, without some means to decipher what it means, it's pretty unhelpful.

I'd ask for an appointment with his new teacher, but until my new powered wheelchair arrives in 3 weeks I'm mostly confined to barracks. Does anyone here have any direct experience of this? Google only added to the confusion

Thanks in advance for any help.