Have you ever seen the difference in writing from Early Years to Year 2, say? I was bemused when dd1 started writing at school and things like 'theis is my haws it hs a greeyn dor' got 'well done dd, I like the sound of your green door', and we got the comment that her writing was 'phonetically plausible' etc.
But it works - you don't make a child a good writer by making them mindlessly copy out corrections. Looking through dd2's Leaving Book from primary, I see:
i has enjyd beeyin in ulyees I lik plaeeyin in the riterin ereey
With the teacher's comment: I have enjoyed being in Early Years. I like playing in the writing area. Great writing A Which I imagine is making plenty of people turn puce as they read it.
I see in year 2:
Dear Santa, Please may I have a pot of new hamabeads, a new stocking and a box of sweets. Please may you bring one of these presnes. Thank you and have a very happy Christmas.
Good. You have used commas very well! Which she had.
Yes, insist on good spelling and grammar - but you don't hit them over the head with it all at once, at 6.