Sadly, Ric.ror. 'Honourable' is one of those strangely restricted honorifics. Younger sons of Earls , children of Viscounts or Barons , but not life peers, are, MPs call each other honourable , High Court judges are the Honourable Mr or Mrs Justice/ the Right Honourable the Lord/Lady Justice and Lord Mayors of London, Belfast or York are 'Right Honourable' as are the Lord Provosts of Edinburgh and Glasgow and Earls, Viscounts and Barons.
And Marquesses, holders of the Order of the Bath and Members of the Privy Council are Most Honourable.
Can't think of any others.