What does you call someone in the Guards?

[Lord Kermit of Birkenhead]

Coldstreamers can be referred to by their proclivities with sheep.  (Not twice to their face) 

[Ben Waterhouse]

Naw- that's the Royal Welch and its goat related.   My mate reminds me that it was the Foreign Legion, as they were only formed in 1915, and 'first entry' was the transfers from the four other Guards.   Good question for a table quiz.

Here's a question - what Brit unit is known as the M4 Regiment ?
(the clue is in the counties spanned by that motorway) 

Derrrrr?

[Ben Waterhouse]

Coldstreamers can be referred to by their proclivities with sheep.  (Not twice to their face) 

Ditto Goose allusions for the Grenadiers...

[Sunray]

Derrrrr?

Answer - The M4 Rifles  = Royal Gloucestershire, Berkshire and Wiltshire Regiment