Winter Holidays dec 26- jan 1

This first thing I would encourage is not to waste time and money returning to London. Weather could be an issue at that time so I would consider swing further south perhaps through the Provence area - Marseile, Nice. And perhaps as far south as Barcelone but that is a bit far. Swing further north into Belgium only increases changes of cold weather.

My first thought was also Provence, and then return or onward flight from Nice.

Travelling round Europe by rail at that time of year can be challenging as many rail lines close for the whole of the festive period whilst major engineering projects are undertaken and there will be a reduced rail/Eurostar and London underground service 26 December (Boxing Day) and 1 January as these are both public holidays and they are two of the most difficult days to travel on in the whole year! Weather may or may not be a factor too.

You have only have 6 nights after leaving London before you depart, so unless you want to spend half your time in transit, I would suggest that you just cover Paris, as there is more than enough there to occupy you for this time. Fly back home from Paris. Alternatively, get the Eurostar to Lille, which is a pretty town and spend 2 nights there, then go onto Paris. The south of France will be warmer, but personally, I would not travel all that distance just for a couple of nights.

If you want somewhere with better weather (almost) guaranteed, do not come to northern Europe in December! If you have no choice but to return to London on the 1st, that is even more reason just to stay in Paris.

Curious if SC is a UK resident. 5 full days in Paris is nice anytime of the year.