rhinestone
that is a good memory your boy has! when I ask DD, a 4 yo july born reception child what she did at school, she responds with 'i don't know' 'i can't remember'! She can't even remember her lunch option if she is having a school dinner day!
We are being very relaxed about it, guided by DD and not being pushy. Some nights she asks to do her school book, sometimes she wants to colour in and practice finding words containing the letter(s) of the day (they have a sheet with pictures to colour relating to the letter, to consolidate school learning), sometimes we ask her to come and read, and sometimes she is just too tired or not interested - we ask the question but do not push it, if she wants to, fine, if not, also fine.
However, she has developed her own thirst for learning letters/words now, so even though often too tired, she wants to know what signs say, she will walk around the supermarket, along the street, reading notices etc while in the car driving past things, identifying letters and some words, or trying to spell out words (often gets it right, for short words). She sometimes talks in her sleep about words/books and so we don't need to push too hard. She can count to 20 and sometimes up to 30 now, she practices it while doing other things, we practice adding and subtracting in normal things we do such as '3 more mouthfuls of food' 'i had one mouthful' so how many more do you need to make 3?' '2? let's count and see if you are right' that kinds of thing, so many opportunities to practice these things without sitting down with a book/paper and forcing them.
DD loves learning, and i hope it is in part because we try to make it fun and let her be the lead. I hope it continues that way, as once she has the passion for learning, the concentration will develop and she can learn application skills.
So, in long, YANBU 