Length: 18.5km 11.5 miles Toughness 7/10. You could join or leave the route at lunchtime by bus.
10:01 Sevenoaks service from London Charing Cross (calls at Waterloo East 10:04, London Bridge 10:10, Lewisham 10:19 etc...) arriving at Knockholt 10:50
Knockholt station is in London Travelcard Zone 6
TFL bus 146 runs between Downe and Bromley

There are two pubs to choose from for lunch in Downe:
The Queen’s Head, High Street, Downe, BR6 7UT (01689 852145)
The George and Dragon, High Street, Downe, BR6 7UT (01689 889030)
Or, a little further along in Cudham, The Blacksmith's Arms, Cudham Lane South TN14 7QB (01959 572678)
For tea, Coolings tea shop 2.6km from the end of the walk is open until 16.30: Arthur’s Coffee Shop and Restaurant, Cooling's Garden Centre, Rushmore Hill, TN14 7NN (01959 532269 )
Remember, these walks don't have a leader so you'll need to download your own copy of the directions from the L=swc.7 web page.