Um, I assume you are Republic. An important difference is that ROI does not have the counter part of the Law of Property Act 1925 ( for political reasons - E de V wanted to be different so there was no land law reform, and land law was left as it was - in the eighteenth century! )
I mean what is your problem - you want to screw the solicitor ? Their regulator may not accept there is wrong doing on the facts as you present them - and they certainly wont fight a case on your behalf.
There is question to title on the property you sold ?
correcting a land title is terribly technical (called rectification I think ) - see a lawyer specialising in this and pay lots of monnay !
The tax man is chasing you on the value difference between value of a free hold and a leasehold ? and his share of the tax
( remember in Ireland there are still land titles which the Brit LPA 1925 ended - entails and god knows what).
You will need a land lawyer who specialises in titles, transfers and tax consequences.
these do exist - I am dealing with one myself following er um imperfect transfer of title in England. They are expensive.
or .... there are no consequences in terms of money, you just feel possed off....
ho hum good luck. I am looking at a bill of a few thousand. (plus VAT )