There is no need to visit the icon. There is nothing there.
Castle Howard - North Yorkshire Moors Railway - Helmsley = A
River Derwent at Kirkham x 2 = B
Helmsley - 1 = C
Wolds Way Lavender - Thornton le Dale - Helmsley Castle = D
Malton Market Place + Thornton le Dale - Helmsley Castle = E
River Derwent = F
Wolds Way Lavender + Helmsley Castle = G
North York Moors Railway = H
Malton Market Place - River Derwent at Kirkham = I
Castle Howard - Wolds Way Lavender - Helmsley Castle = J
You are looking for a small chunky magnetic container hidden at the location which you will hopefully work out from the information given.
The cache is hidden at N 54 AB. CDE W 000 FG.HIJ