ok, here is the email I sent but go ahead and use your own wording. It's good if it comes from the heart.
"Dear(first name of your MP),
At a time when the nation has pulled together and made huge personal sacrifices to fight the spread of the covid-19 virus -and with DISASTROUS consequences to the economy- many people are rightfully enraged at Dominic Cumming's flagrant disregard of the lock down rules that he himself had a hand in making. It would appear to a lot of people that there is one rule for the people, and another for our political "elite". I hope that you can see that the behaviour of Cummings was unacceptable and Boris Johnson's efforts to defend his actions were very poorly judged. I would ask that you be among those Conservative MPs urging for Cumming's resignation.
Sincerely "