I suppose that the question which needs to be asked here is:
'If the child cannot spell well, or use grammar correctly, is it appropriate to be marking the work against other criteria?'
In other words, pretty much all the teachers here are saying that they mark work against the success criteria set for that piece of work, and generally will not pick up errors that are unrelated to these success criteria.
The question we were posed, and which caused us to think really carefully about how and what we marked in English, was 'If a child is not writing, spelling and punctuating simple sentences correctly, why do we set and mark against any other success criteria?'
It is slightly different in other subjects, where one can argue that 'content' may take precedence over 'precision in written English'.
However in English, we are moving towards a policy where we mark first and foremost against success criteria based on basic grammar, spelling and punctuation (within reason - a child really going for an ambitious word but spelling it incorrectly, or learning a new grammatical feature such as the use of modal verbs, isn't penalised, whereas one spelling 'which' incorrectly always is), and only once that is secure do we mark against specific genre / content criteria.
Essentially, children pick up what you value. If you always mark against 'content' success criteria, that is what they value too. If you shift to mark against technical success criteria, they will respond too.
I'm not suggesting that every piece of work has to be marked against everything possible - that's not pfeasible, based on workload. However, if there is only time to mark against one set of success criteria in primary / early secondary, then perhaps it should be against grammar / spelling / punctuation until those are embedded and ingrained.