Hello Aye,
Many thanks for your wise comments. I suppose I have suspected my old demonstrative teaching technique has been inappropriate for some time as friends have said to me but I needed someone independent to alert me to this. In the beginning I taught only once per day and demonstrating was not so demanding - then with 4 classes in one day I should have adjusted my approach. Since your kind message I have at least scaled down my demonstrating to half the class time and will continue to do so in the coming weeks. This I feel I owe to my students who have been with me some years and for whom an abrupt change might be offputting - also for my self. I have also included a separate pranayama and shavasana for myself when student have left the studio and this has reduced my tensions.
Once again many thanks for your message.
Best
Yama