Would you class this as lack of progress?

[littlemiss06]

Yr 4 daughter has asd, attachment disorder and spd

Ended yr 1...1C across all subjects
Ended yr 2...1b reading 1A maths, 2C writing
Ended yr 3...1A reading 2C maths, 1A writing
Spring yr 4...2C reading, 2B maths, 2C writing

Adequate progress or not and if not is it ok for a lower ability child or should expectation still be the same as 'average' ability

Lack of progress means no improvement and clearly your child has made progress. Although the government does not acknowledge the existence of sub levels they expect children to make the equivalent of 2 sub levels progress per year eg. 1a to 2b. However not all children will make the same amount of progress in each year and progress often comes in leaps and then can stagnate, this is why progress of levels is measured by key stage.

Your daughter made above expected progress in writing in year 1 and then dropped in year 2. Looking at this data alone I would be inclined to suggest that her year 2 teacher made an error in assessing her.

No all children will make progress at the same rate. If you are concerned you need to speak to her teacher.

Generally expected progress is taken to be 2 full levels across a key stage which works out as about 3 sublevels per year in ks1 and 1.5 in ks2. As mostly said, children don't always make progress in a linear way, but those results suggest a sustained pattern of poor progress over several years. It looks like she's making roughly a sublevel a year, which is low.

Avg progress goes with avg targets.
Below avg progress goes with the reasons why she tends to be below avg.

what is school doing to support her, and what kind of secondary options does she have?