Hi Niall, 

As you rightly say, the French do not use the imperial system nowadays but it is always difficult to translate such measures into metric ones. 

In this context, the word 'pinte' ( about half a litre) doesn't offend me. I always translate miles to a rough equivalent in Kms when I am talking so that people understand the actual distance.

To me 'chope' refers more to the container than the beer.

Here is an interesting page on the different terms used for beer measures -

http://univers-biere.net/degust_contenants.php