I have been working out the actual miles i need to do and;

Stage 1: London–Folkestone 119.0km (73 miles) - we all do this.
Stage 2: Calais–Reims 320.9km (200 miles) - min 132 miles
Stage 3: Reims–Dijon 316.5km (200 miles) - min 132 miles
Stage 4: Dijon–Valence 314.4km (200 miles) - min 132 miles
Stage 5: Valence–Aix en Provence 234.5km (145 miles) - min 100 miles
Stage 6: Aix en Provence–Cannes 176.4km (109 miles) - min 72 miles

The minimum distance is 2/3 of the total which is the minimum each rider has to do to be a qualify as a finisher. 
oh dear!