I have heard this is something a few have done before when getting homes from family in Dublin and trying to reduce the value as it was going to benefit by PPR Relief going forward. Mind you if you are going to sell it there is no point in doing this but if you are not consider the following.
Make a bit of a mess in the house. Leave a few old papers thrown around, rubbish, beer cans etc on the floor, put up a bit of Graffiti on the walls, pull out fittings that are no longer needed, throw the mattress off the bed and make sure no bed is made, screw out a few sockets and leave a few wires in plain view, take out alot of the light bulbs, get some dirt and stink out the toilet, let the grass grow high, peel out any soon to be gone wallpaper, put a bit of water on the wall all prior to getting in two nice agents in to Value the property for inheritance rather than sale at a fixed fee say €250 each and make sure they take a few pictures. All the above are very cosmetic and easily restored but make a house look awful. I guarantee if you have the heart to do it the Value will come down by 25-30% odd and a coat of pain and a few hours work and a strong stomach will restore it back to normal. Its very feasible especially if you plan on redecorating it anyway there is alot more you could do if that was the plan. Let the agents know the BER is an X Rating and the house was trashed by youths/addicts etc. Tell them you think it might have to be rewired. Tell them to watch their step etc etc.
That could be a 33k saving at a cost of 1k odd.
If the idea is a sale it won't be of any net benefit as you will be selling the house for x anyway and if you don't have to pay CAT you will have to pay CGT, however if the plan is to keep it and some day live in it as a PPR or rent it long term then why not. Nobody has to be dishonest and the valuations are 100%