Certainly happened whilst they were being tested. Not in service though.
I have found this picture online from the very early days.
Not your everyday formation with 319004 and 465001 in tow passing Hall Place between Crayford and Bexley running as 5X96 13+14 Slade Green depot to Strawberry Hill depot. Friday 21st August 1992. 194-10.
www.flickr.com
There is an interesting comment under that picture about a test being done more recently, albeit probably over ten years ago now, to see if it still worked for recovery purposes.