Planted ’06. Excellent in places where there good shelter. Soil good alkaline. In more open ground, plants failing to thrive, even dying. Have replaced some to no avail. Site somewhat exposed but not overly so. Would planting on a gravelly mound help? Feel that wind and wet of recent years the problem.
Yew does not like wet ground, even if it only gets wet in winter. If the areas that is sheltered is also better drained and has not been disturbed, so much the better.
It is possible there is soil compaction or some other impedient to drainage, and this should addressed by breaking compaction and/or putting in a land drain drain. Planting on a mound would help but it would be better to solve the drainage problem.