Both the append query and feeder table are solutions but they take time.
You could set the Format of the Field in the Table to be /1000 (there are problems with doing this when you get to 1999 if you have a large database). The first record will start at 1001.
If the pupil took the easy option and started it at 1001 would this be enough to say the pupil has not passed that Task in the assessment? I would hope not.
Whatever way it was done it the supplied files to get it to start at 1000 is not obvious.