Great Western Coffee Shop

I^m planning a couple of trips from Bristol over the next couple of weeks.  The first being this Friday departing as close as possible to midday, the second being next Tuesday departing at 0900.
I want to drive to either Parkway or Filton Abbey Wood, park and go on from there.  My preference would be Abbey Wood as the parking is free compared to the ^8ish pounds that Parkway would be.  My concern is that the car park at Abbey Wood is quite small and as I am arriving after morning peak I may arrive and not be able to find a space, meaning I will have to find somewhere else nearby (not easy when you don^t have local knowledge) or end up going to Parkway anyway and scuppering my finely tuned plans.
Does anyone have local knowledge on Abbey Wood as to whether parking spaces are easy to come by or would it be better just to go to Parkway to be on the safe side and take the hit on the parking cost?