Ditton Slipway

Note the current slipway is NOT at the end of Ferry Lane as you might expect.
The Bing Aerial view shows it best with the road labelled "Ditton Reach".
OpenStreetMap also shows it well. StreetMap not so well.
There is a track to the river at the slipway
Leave A307 on Ditton Reach.

Left bank off the A307 Portsmouth Road

Ditton Reach Slipway, 1999
Ditton Reach Slipway, 1999

The boy fishing inspected the punt and decided that a 25 horsepower motor would be about right.  There had been moments in punting from Cricklade to Teddington when I would have agreed with him.
Actually a year or two (or rather forty years ago!) when with a small family I did run a punt with an outboard for occasional use, 4hp was about right - enabling 5mph - which is all legally allowed anyway!
Notice that the far bank is grass and trees.  There is plenty of greenery here. Two miles further up there are sections of apparent countryside.