I know it is difficult to say something but part of me feels you should.
DS1 was at the same levels at the end of Y1 and the school have really let him down this year as it is a stand alone infant school he has not has a 'group' to work with this year so has been worknig on the same literacy level all year with no attempt to stretch him. He got 100% in his L3 SATs in Y2 but NC level for Literacy the same as 18 mnoths ago according to teacher assessment! I wish I had brought it up earlier but left it too late as kept thinking that things would change.
Numeracy and writing has improved but not dramatically.
Those levels should be sent to the new school by the old school. I'd leave it a while and see what the new school do (if anything). I will warn you of the fact that the new school may be tougher with their levelling though. As a school governor I've seen teachers in the same school disagree over the levels of certain work!
My DD has roughly the same levels at the end of y1 and I'm worrying enough about y2 in the same school so can imagine your worry over a new school.
I've just reread your OP and I have to apologise. Those levels are special! I was reading it as an end of KS1 situation, where it would be at the good end of normal, whereas you said it was end of year 1, which is very special. Well done to your son, OP.
However, I'd still be wary about asking the school any question that may suggest that they are not 100% on top of the situation... no matter how gently you phrase it, there are a lot of teachers who will hear that message and will instantly retaliate by labelling you "pushy", with the unspoken subtext that you should be rebuffed.
Those are about the levels that DS2 is at (we are in Wales so things are labelled differently). We were looking at moving areas this summer. At his current school he is on the G&T list, mainly as it is a small school, so to cater for his differentiated work he changes classes. At his last IEP meeting, his teacher was saying that they probably wouldn't identify him as G&T at a bigger school as there would be more children working at similar levels within the year group, so the message going from the school would be "bright" but not exceptional, which I think probably sums DS2 up to a tee.
I think you should wait. The results your son just got are good but they aren't exceptional (which doesn't mean that he hasn't the capacity to be exceptional, only that he isn't demonstrating it in his class work just yet).
I can't think how you would phrase such a request at this moment, without the new teacher mentally dismissing you as a pushy parent. Sorry.
At level 3c for all the literacy work and level 2a for all the other columns He moves school in September do you think we should be asking the new school for extra work for him or should we sit and wait for a bit to see how they added him? I just don't want him to be bored as well as having to forge new relationships