I've been through two years worth of the 'rules of the route', a good few weeks ago now, and there are no diversions via Banbury or into Waterloo mentioned again. I'm 99% sure (without checking it all over once more) that there is no planned block of the whole station, ie mains, reliefs, Southern, and the western bays, in all that time.
This total block is driven by the 'one off' signalling transfer to
TVSC» , if it was only the Caversham Bridge they were replacing there'd be little reason why the mains and everything south of them wouldn't still be open.
Paul