I have done some research and I don't believe that it is illegal in NZ to shoe a horse without training but it probably should be! After reading up on hoof care I have realised how important it is to have someone who really knows what they are doing - even if he has been doing his own horses for years and they seem fine.
Having spoken with other people a great farrier is worth their weight in gold and usually has more customers than they can handle, hopefully I can find someone like that who has space for another horse. I also have a mini who will be needing her feet trimmed shortly and would like to find some who has experience with the wee horses too!
I am still feeling annoyed about the whole situation and considering how overprotective his last owner was (and still is now that he is mine
) I'm surprised that she was happy for his feet to be done by someone unqualified. Ah well, at least I am learning! Thanks all for your advice.