Good luck to Briony! I'm sure she will have a wonderful time - and it's a new chapter too for the family, with all those visits to a newly-independent daughter to look forward too, and the hols when she returns.
Speaking from experience here - all my three babes went off to university, and it was VERY difficult saying goodbye and leaving them in their rooms (oh, how guilty and mean I felt!). But we had a super time on all our visits, and discovered new places and new things to do, new conversations, and had the absolute delight of watching them grow in confidence, personality, independence, fun ... and at the same time, the odd new experiences of being the mum-on-the-end-of-the-phone, when there were the difficult times ...
I hope you all have a great time, in this new chapter.
Good luck to Lukas too.