if my recent visits are anything to go by you stand a fair chance of one on a Reading to Newbury stopping service (assuming they are still on hire). I managed all three C2C 387s that were borrowed by GWR though needed 3 visits to do so. There are two diagrams to cover the hourly Newbury stoppers. On my last visit 387306 was working the 0802 from Reading. The other diagram was a GW 387. There is a nice cafe just down the road from Newbury station towards the town centre that does a nice breakfast (lunches available as well) sit in or take away.