Originally Posted by NGalitzine
Why would he even be wearing the neck badge if he was not wearing formal attire?
Exactly. Guides to wearing honours and awards consistently state the positioning of a neck badge should be suspended by a miniature length of the order's riband, passing approximately one centimetre below the knot of a tie (if in a suit), or bow (if in black or white tie).
The regulations for wearing neck badges of orders in uniform differ slightly, depending on the order of dress given for the occasion in question. In all three services, if wearing service dress (comprising a conventional straight tie), the positioning of the highest neck badge to be worn on the day, is the same for civilian attire (approximately one centimetre below the tie knot). If the person in question holds additional honours comprising neck badges, they are worn suspended through the button holes of the jacket in order of seniority, allowing approximately one centimetre of the miniature length riband to be visible.
For those orders of dress where the jacket is fastened underneath the chin with a high collar, rather than the neck badge being worn suspended beneath the tie knot (which would be absent in this instance), the neck badge is worn hanging through the collar opening, again suspended on a miniature sized length of riband, protruding approximately one centimetre from the collar opening.
There is no provision for the neck insignia of an order to be worn in place of a tie, where a tie would otherwise be worn. Nor is there provision for the wearing of insignia apart from occasions requiring uniform, evening wear, or suit (lounge or morning). I hope that helps.