Something like this perhaps (I found it more effective to send letter, because email contact was bogged down and email was just returned after 3 days):
Boris Johnson
House of Commons
London
SW1A 0AA
Dear Mr Johnson
The monarchy exists only with the consent of the people and is accountable to the people through Parliament.
When do you plan to hold the Duke and Duchess of Sussex accountable for their treasonous disloyalty, as demanded by the overwhelming majority of the British people?
I respectfully request that you initiate action to remove Harry and his offspring from the succession. The justification for this is as follows:
Tempting as it may be to bury your head in the sand and keep passing the buck back to Her Majesty the Queen, this is no longer a purely private family matter. The Duke and Duchess of Sussex have traduced not only their own family but also our constitution, the fabric of British socitety and the people of the United Kingdom and the Commonwealth. They have deliberately exposed us to vilification from around the world and incited division where previously there has been cooperation and commitment to improvement for the common good, of which we should be proud. They have justified this action with a catalogue of lies, cruelly brought before the public in the US and worldwide for maximum humiliation and personal financial gain. It is simply not acceptable that they should be permitted to do this from a position of British royal status.
Meghan and Harry have chosen for themselves a path which is incompatible with their retention of royal status. Royal status should be reserved for those individuals who assist the Monarch in fulfilling the Monarch’s role. That role is to sustain our hereditary constitutional monarchy, uphold our values (including integrity, free speech, fairness and natural justice) and act as the glue which binds us together within the UK and with the people of the Commonwealth, presenting our best face to the world and facilitating shared problem solving and mutual support. It is a role which necessarily comes with obligations and constraints – so, for example, it is by its nature a role which is in the public eye, which cannot be done in secrecy or under standard terms of employment, because it takes precedence over other interests. It cannot be combined with political activism, accepting freebies or making commercial deals for personal financial gain where conflicts of interest cannot be avoided. In return for this undoubtedly onerous commitment to public service, we bestow on royal persons significant wealth, privilege and opportunity.
Any and all persons with royal status should believe in the role, undertake the obligations with enthusiasm and be prepared to observe the inherent constraints. Harry and Meghan clearly do not – they have told us as much and that is their choice. The Queen, with the assistance of Parliament as necessary, should therefore remove all of their royal status – by which I mean titles, place in the succession (both Harry and his offspring), and any continuing funding from the Crown Estates or British taxpayer.
Yours sincerely etc