If an officer has a title, or a courtesy title or style, he is addressed in the opening of a letter and in speech in exactly the same way as any other title-holder. It should be noted, however, that some titled officers prefer to be addressed by their Service rank.
If Admiral Sir Guy Jones expresses his preference to be addressed 'Dear Admiral Jones' instead of 'Dear Sir Guy', this should of course be observed.
On an envelope the Service rank appears before the title, except 'His Excellency'.
The appropriate letters signifying Orders and Decorations immediately follow the name, except that if he is a Baronet, the abbreviation 'Bt', or 'Bart' immediately follow his name, followed by letters that signify Orders and Decorations.
His Excellency Admiral the Lord Chiswick, KCB
Colonel Lord Edward Manners, DSO, MC
Wing Commander the Hon Edward Smith, DFC, RAF
Lieutenant Commander Sir John Smith, Bt, DSO, RN
According to title or style, unless the officer concerned prefers to be addressed by his Service rank.
Note: 'The Hon' is never used in speech, e.g. Major the Hon John Brown is known simply as Major Brown.