Following the Arun, then through Amberley village and Parham Park. After a steepish climb we take the South Downs Way back to Amberley.
Buy OPDR to Amberley. Dep. Victoria (Bognor Regis/Portsmouth Hbr. train) 09.05 arr. Amberley 10.29 (Clapham Jct. 09.12, E. Croydon 09.23). Train divides at Horsham; listen to announcements and be sure to be in the right part, usually the rear. Picnic lunch in Parham Park. Drink stop at the Crown Inn in Cootham OL10 Leader Mike Coyle

Supplementary information from the leader:
Morning: 9km long, fairly level. About 2.5 hrs
Afternoon: 10 km, with steepish climb at start of 250 metres. About 3 hours walking. Some on an exposed ridge so bring suitable clothing. There are also sections with brambles and nettles so long trousers are recommended.

Weather forecast currently is sunny with a maximum temperature of 26C. Bring sun cream, suitable headgear and plenty of water as well as your picnic.

People who just want to do the morning walk can take the 100 bus, run by Compass, from Cootham Village hall to Pulborough train station. It runs hourly at 12.25, 13.25 14.25 etc and takes about 10 minutes (Pulborough is the station before Amberley so is covered by your Amberley ticket).

Photo: Across the Arun (1) by Peter Trimming