Hi Saffy- How interesting your physical therapist has put you down for breaststroke, given that the notion of reaching is typically a no no. Working in a warm therapy pool [92 degrees F] my therapist had me doing a good many exercises, none of which involved reaching above the head, but did involve a variety of stepping exercises, lunges, side stepping, marching, walking, lifting my arms with hydro paddles in hands for resistance up to my shoulders from the waist position, both to the side and to the front, and a exercise also using said paddles in a motion like flapping my wings from a shoulder height out to side then meeting in front of me. Again, again, and again. It would take about an two hours to complete all of the pool exercises, then it would be off to the deep end of the pool for "bicycling" and hanging with weights on my ankels as though to provide some traction.

The actual use of swimming strokes was never part of my therapy regimen, but then, perhaps as between different therapists there are variances of approach.

Hope it goes very well for you,
Mark56