Gordon a few suggestions for you, I don't know how well you know Abingdon so if you want any more info on how to find/get to these let me know.
One of go to places mainly because its very close and easy to get to is St Helens Wharf, its nearly opposite to the cc on the other side of the river.
Starting by the church you can shoot on or above the slipway, shooting towards the sunrise
Mist Under Ock Bridge by
Graham Norton, on Flickr
If you walk away form the church just before the bridge you get a fairly decent view the other way down the river.
Misty Morning by
Graham Norton, on Flickr
Cross the bridge these is a little garden with some nice views and if you go just pass that you can get some nice views of St Helens Wharf and the church (there are a few benches there)
Black & White misty morning by
Graham Norton, on Flickr
You can get some lovely views from the other side of the river (the cc side) from close to the bridge, has you got into abingdon just left of the bridge you can get some lovely light on the Church, depends when you are coming you can to many boats along the bank.
Also if you walk upstream right from the same bridge there are possibilities between the bridge and the weir.
Further afield Whittenham Clumps are nice going right from the car park you can get some lovely skies over Brightwell Barrow
Pre Dawn at Brightwell Barrow (1 of 1) by
Graham Norton, on Flickr
Also some rather nice benches here
A Sunlight Bench by
Graham Norton, on Flickr
Another possibility is Days lock at Little Wittenham - go into Little Wittenam and park opposite the church carry on walking down the lane cross the river turn right out of the gate.
A Pair of Posts by
Graham Norton, on Flickr
If you want any more info or help just me know.