They may also find the following useful. It is a paper prepared by the clerks of the House of Commons, so is a reasonably objective view of the Brexit situation as of now (although it may be more advanced soon….).
The link to the RIFT web site may be useful to those who want to know what is going on with Brexit and how best to continue living in France. Whilst it is avowedly pro-remain, the information should be useful to all UK citizens, irrespective of their Brexit vote/opinion (or lack thereof).