I agree with CianMacLiam i prefer the Irish maps to the Northern Maps. I think the Irish maps are more specific as to what they are actually pointing out. In fairness ive only found two or three sites so far where something is marked but is now gone so I think they are in reasonable shape. If you check the Archeaological Inventory (if your area has one) then that will normally be more up to date. The map i use for around where I live is quiet old (maybe 10 years) so possibly more up to date ones have been published since but I doubt it.