For run of the mill tax returns and general advice on farm accounts and finance matters you do not generally need the services of a tax consultant. A professional accountant in practice would have sufficient tax knowledge to handle your affairs. Of course some accountants in practice are also registered tax consultants so you can get the best of both worlds as it were.
If you need specific tax advice on matters of a complicated or potentially contentious nature, then Alan Moore would be one of the best names in the country. I have dealt with him on a number of occasions and was always satisfied with the service. Depending on your area of the country, if you need specific tax advice there are a number of other tax consultants I have dealt with and could recommend.
On a fees note, the last fee note I had from AM was billed at I think €300-350 per hour which would not be unusual for advice of this calibre.