http://www.southernrailway.com/your-journey/plan-your-journey/improvement-works/ said:No Southern services between Clapham Junction and Watford Junction on Sunday 19 January 2014
Engineering work is taking place between Clapham Junction and Kensington Olympia closing all lines.
Southern services between Clapham Junction and Watford Junction will not run.
Passengers are advised to travel to London Victoria and use LUL services to London Euston changing onto London Midland services between London Euston and Watford Junction.
Planning your Journey
To get options for your journey on London Underground, please use the Transport for London Journey Planner
For full details of these changes and the impact on your journey, please use the National Rail Enquiries Journey Planner
There are Southern Advances from Chi to Bletchley from £5.30 (with the railcard) for going up on the Friday via Kensington Olympia.Leave Friday pm return Sunday, any ideas to make it cheaper.