I find myself wondering whether it would be possible to rig a large fender or small buoy (not junior) to take out on training sessions to use as a turning mark. I am thinking fender rope weight or small anchor to drop off and collect. The benefits especially at low water would be a safe point to aim at and turn round.
We have been given some smaller race buoys (x4), by Jules Hewwon an RNLI mate and that may be what Martin is referring too. HOWEVER the anchors and weights need to be returned and will be on Wednesday evening, just so you are aware.