I thought the correct terminology is 'copped'......

You could well be right with 'bash' referring to travelling on a particular line.
Interesting (but quite long) article on
WikiPediaI'm going for "copping" as collecting / gathering a line, picture, or something else for the first time. "Bashing" is the act of travelling a line, or using a service, for something beyond the bare requirement of somehow getting from A to B, and so can be repeated.
I copped the Melksham to Chippenham service about 15 years ago. I have bashed it a number of times since (travelling with intent other than just travelling between the end points), and I have travelled it as part of my journey a heck of a lot more times!