In the mid 60s my father ran a 3.8 Mk 2 and it had a cubby box arm rest between the front seats. I used to sit on it or stand on it and put my head out of the sunroof. Those were the days before mandatory sear belts in the UK.
I now have a 3.4 Mk2 and am looking for a Henley box. I think they are so called because they were an after market option offered by the main dealer called Henleys.
Does anyone make such a box these days?

 

https://valvechatter.com/?cat=1265

Originals sometimes appear on eBay at, imo, grossly inflated prices. The link above gives some info on making one, which makes sense as an old one will inevitably require a lot of work.

 

This is what the box looks like mounted between the seats - it is an indispensable anti-slide addition!