Hi Morningnovice:
MN has a learning/ resources page (if you click education on the menu bar - it's the second column from left - one above 'tutoring'.)
Anyway here is what Mumsnet have to say regarding expected progress through NC Levels: www.mumsnet.com/learning/assessment/progress-through-national-curriculum-levels - scroll down and you'll see the first table explains how many sub-levels progress expected Key Stage 1 (years 1 & 2) and Key Stage 2 (Years 3 - 6). Sub-levels work c to b to a - with 1c being just working into NC L1, 1b being working within NC L1 and 1a working well within NC L1, possibly showing signs of working to NC L2.
So scoring 1a now (expected attainment end Y1 according to MN - although tiredbutnotweary says her school uses 1b as the end Y1 target) and on track for 2c at end of Y1 is very good - looks to be 1 full sub-level ahead of expected progress.
One thing I will advise is schools do 'game' this. They don't want pupils doing exceptionally well - puts pressure to extend teaching to higher NC levels than they can support (e.g. our school is really struggling to deliver L6 curriculum to a few brighter children each year - so they tend to end up spending their school day in Y6 helping less able pupils - free TA basically)
They also want to show expected or more than expected progress. So somewhat suppressing performance (frequently you'll see on MN a discussion which goes 'I don't understand DC finished Y2 on 3A but is not 3C in Y3' - the usual excuses: loss of learning over the summer/ change in schools leading to slight differences in NC Levels, etc...
And to add to our parental joy (THANK YOU GOVE - YOU MUPPET!): www.gov.uk/government/uploads/system/uploads/attachment_data/file/276674/National_curriculum_and_assessment_from_September_2014_fact_sheet_update.pdf - see page 2 - under assessment.
So basically from next year it will be a free for all - with schools pretty well deciding how to spin performance and parents being unable to reasonably compare performance in a school year against national or local standards. Apparently the only points where NC Levels will remain is KS2 SATs (results so late to parents nothing can be done) and KS4 GCSEs (again results so late to parents nothing can be done).
Although I respect that the present system has faults, parents have got used to it and are starting to work out what expected progress is and how their child is notionally doing. Total removal of some overarching framework parents can plug into means that for many we will have no reliable scale of comparison between our child's school's say so on performance and local/ national performance except late in the day (at the point of getting KS2 SATs results/ KS4 GCSE Results. This policy rather looks like a train wreck waiting to happen.
HTH