The plan:

04/07 - Dan (in office am) rides/trains over from Bristol to London
05/07 - Work day (and dinner with Becky)
06/07 - Work day, Final kit checks
07/07 - Ride Epsom to Hampshire, as "Prologue".
08/07 - Depart portsmouth evening 17:00 on Cap Finistere
09/07 - Arrive Bilbao (18:00) (A on map)
10/07 - Cross border into France
11/07 - The pyreneean foot hills
12/07 - Arrive at B on map (Lourds) [300Km since Bilbao]
13/07 - B/C on Map Climb col-de-tormalet (Tour de france is on Stage 11, Blaye-les-Mines to Lavaur)
14/07 - Watch Tour de Fance Stage 12, Cugnaux to Luz-Ardiden (Col-de-Tormalet), Head east for stage 14
15/07 - Finish near Siex (F on map) for stage 14 (Tour de France is on Stage 13, Pau to Lourdes) [225Km since Lourds]
16/07 - Watch stage 14 (F) Finish at H on map for Stage 15 [155Km since Siex]
17/07 - Carcassonne, watch stage 15 (rest day)
18/07 - Ride to Beziers [75Km since Carcassonne]
19/07 - Spare day: Beziers, Swim in the Med or catching up
20/07 - Am train to Millau, pm train Millau -> Paris
21/07 - Paris (buy crepes')
22/07 - Eurostar to London
23rd/24th Dan ride/train Epsom -> Bristol
25/07 - Back in the office :-)

Google map of the route