I remember bootstrapping a PDP8 from the front panel switches, and building one of the first Altairs in Europe - so that should fix me as a correspondent of mature years.
I'll start by repeating a previous responder - all parliamentary outside work is listed in the members interests register - i.e. it is not hidden behind closed doors.
An MP's salary is less that a school headmaster and substantially less than a GP or Dentist.
How on earth do you expect professional people to become MPs, while forbidding them to take on additional external work - particularly if they have served their country in one of the highest offices, and were paid at rate which would make even a junior banker sneer.
I certainly would not consider it.