Just because Hornby's model of the Pacer train won't couple to their model of the Mark II carriage doesn't mean to say that the real thing can't be coupled.  Here Railbus 004 makes a buckeye connection with the Buffet First Coach.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/11779319@N07">Alexander Cunningham</a> from Hawick, Scotland
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/cessna152towser/8039943608/">Coupled Up</a>