West Tanfield village is on the A6108 out of Ripon. As you approach Ripon start following the directions for Lightwater Valley, which is located roughly 2/3rds of the way along the A6108 to West Tanfield. There is a big clock at the junction at the start of the A6108.. Continue past Lightwater Valley (which is located off to the left of the road) towards the village of West Tanfield.
The cricket ground is located on the right hand side of the road (on the Ripon side of the river Ure), shortly before crossing the river. If you end up going over the bridge and into West Tanfield, itself, you have gone too far and just need to double back on yourself.