Goodness you have a challenge! I think you will have to have a timetable where you know which groups you will be working with as a focussed task during different parts of the week, so that you don't end up having nursery with the TAs all the time. Does your LEA promote daily do's? You could use Jolly Grammar alongside Jolly Phonics to stretch the more able. Have you seen the document "A toolkit for Foundation Phase Practitioners" on the ESTYN website? Might be of help. Also I would remember stage, not age. Some of your Reception may be working at a higher level than some of your year 2s, so you can plan accordingly. Good luck.