Assuming probate has been taken out, it really depends on how much the land was valued at in the estate. Sometimes in these circumstances, the land may have been valued low in the estate, and now with the new zoning the value may have risen dramatically. In certain circumstances, a corrective affadavit may be filed with the revenue, depending on the timing, however it may not benefit you at all if you are well over the CAT threshold as you will either be paying CAT or CGT- both are 20%, so it doesnt matter much which you pay. AFAIK the cost of planning applications are not an allowable expense when calculating CGT, but most people just whack them into the computation and leave it to the Revenue to either allow or disallow.