Hang on a second, €2,350 is 1% of the sale proceeds of €235k, not 1% of the taxable gain of €65k, or of the (unquantified) CGT liability. Otherwise the bill would have been (at most) €650! Hence there is no basis for alleging a breach of ethics here - at least on the basis of the information given.
It is increasingly commonplace for accountants to set fees for CGT/CAT etc as a % of the sums involved. This is on the basis that CGT and other capital taxes work involve higher risks for the professional (reflected in turn in professional indemnity insurance costs).