Thanks picnic. Unfortunately we broke the bank paying for the tickets, so haven't anything left to go somewhere else. Also, we have to fork out at least £100 for both dogs to get passports. We're going to move our trip to the Christmas break, purely because we'll lose the money we've paid otherwise. None of the dcs wants to be away for actual Christmas though, which is a pain as it turns out that with dh's new job's Christmas closure, we could actually have gone for longer.
If you do plan to go to Ireland, it's worth noting that not only do you need the rabies vaccination at least 21 day prior to leaving, your dog had to be microchipped prior to the vaccination and to enter Ireland he must be treated against tapeworm no greater than 5 days and no less than 24 hours before you travel - although you don't have to do it coming the other way.
The whole thing is farcical, as both the UK and Ireland are Rabies and Tapeworm free.
It's a massive money making scheme for the vets and drug manufacturers, but I've read today of a couple of cases of animals being impounded, so seriously not worth the risk. In one case it was a cat and the owners couldn't afford quarantine fees, so it was pts. Out-bloody-rageous given that it couldn't possibly have had rabies and was therefore no risk to anyone. On another forum, one lady travelled fine with her two dogs in September, but later found out other pets on the same journey were impounded - which is in the nature of spot checks I suppose.
Ridiculously there are no plans to enforce pet check in, so all pets can have their chips and passports checked - it seems it will just be random checks, so some will get away with it, while others who are less lucky will get caught if they don't pay £££s and comply. 
Anyway, enough ranting about all that - we've made the decision to postpone instead of cancel, the dcs are still upset, but we can't do much about that and at least we still get to go. After this time there won't be an issue, because as long as we keep up with the vaccination boosters it'll just be ongoing.