AFAIK when the deceased left no will probate is not available: it requires a grant of administration.
It is incorrect to use the word beneficiary also in this context, equally there are no executors
See here
http://www.irishstatutebook.ie/1965/en/act/pub/0027/sec0069.html
As pointed out earlier you spent money on an asset that is not yours, you jumped the gun.
You also jumped the gun offering an asset for sale that was not and is not yours yet.
Have you issued and signed a normal contract for sale with you as the owner? if so you are exposed to the purchaser suing you under a number of headings.
On the issue of estate administration expenses, in the case of a will the law is very clear that no expenses, other than funeral and lawful debts at time of death, can be charged against the estate unless they are specified in the will, this is why wills have the clause allowing lawyers charge for their work. If a lawyer drafts a will and forgets to add in this clause then he cant charge for probate work
Similar rules apply for administration so your 80 cannot be charged against the estate if thats what you have in mind, its not clear from the post.
If all the work was vouched etc and above board the purchaser may be willing to pay you for the expenses, however once he sees you are over a barrel.....
The taxes due here are inheritance tax due on the 160 plus any other assets less funeral expenses etc so lets say 160.
Then you sell the house for 230 and you pay CGT on the 70.
In passing, have you got a BER as part of the exercise [broken link removed]