OMG I’ve just heard that you’ll only be able to take £50 (Cash or Travellers Cheques) with you when you leave the UK to travel to France. You’ll also need a stamp in the back of your passport to confirm that’s all you have on you. 
Ahhhhhh…just like ‘The Good Old Days’…
(gin’s kicked in !)
So Darren, you can either go with
or you can go with the information in the link Jane posted in the very first reply to your question, which says:
No. The world is simply not the same as it was in those days. The EU is now much more concerned about the security of its borders, both from an immigration perspective and also from a anti-terrorist point of view. The EU’s interest is in protecting itself and its own, and life as a third country national - an ‘outsider’ - is very different from the way things worked in the 1960s and early 1970s even though parts of it are given legal framework by a number of specific EU Directives.
All British citizens living in the UK and wanting to travel to the Schengen area will need to register under the ETIAS scheme - the European Travel Information and Authorization System.
This is a new and completely electronic system, expected to be in place by 2020, which allows and keeps track of visitors from countries who do not need a visa to enter the Schengen Zone.
Its prime function is security, but it’s also designed to help manage borders and impede irregular immigration. Registration will have to be done online before travel. You can find out more about ETIAS here.
How ‘balanced’ Anna…
Think I’ll wait for the official post-brexit stance, legislation and implementation here in France before any of my knickers get in any kind of twist 
Please don’t twist your knickers Simon, it could be painful 
and I don’t think you need to, because one thing that does seem pretty certain is that the length of time a Brit has been living in France/the EU is going to be a significant factor in what rights they have after Brexit. Since you’ve been here for a while, you’ll be among the least affected.