I can't really recommend accomodation in Newbury - not having had the need to use it. Byng's options are probably reasonable.
The Chieveley travel lodge is in the motorway services, not the most wonderful surroundings but easy to get to.
Pilgrim's is not really in Donnington - which (in my book) begins a few hundred yards north, on the other side of the river Lambourn - but it's fairly convenient, and easy walk from the town and seems to have ample parking.
The Bacon is in the town, very convenient, plenty of parking and one of my favourite bars - but almost certainly more expensive. The food is okay, typical of a pub chain, cheapish and plentiful rather than gourmet.
There are others, the Newbury Tourist Information Centre should be able to let you have details.