Marseille 2 days
Luton to nice - 43
Nice to Heathrow - free (avios)
Train 65 return nice to marseille
Hotel 40 (half of 80)
Ticket 27
Taxis 30
Booze 70ish
Meals about 150 with a Michelin star lunch included. Very reasonable.
£425 .... not bad not bad at all. Especially as a week in St Tropez...