A very important thing, when it's for a disabled passenger, the modifications MUST be at least 10% of the pre-tax cost of the vehicle. See [broken link removed] . Or Revenue will not give the VRT/VAT relief. This can be a pain if the cost of the seat is be less than the 10% rule. The adaptation people then have to do some more work say on other extras, even if not strictly needed by the person to ensure expenditure meets this.
The medical certificate is a "Primary Medical Certificate" this is done via the HSE and is not just a cert from your GP. However once the person has one, it's good for any future car changes.
Check if the garage has done DD claims before, some are very good and help with the paperwork and have a good relationship with adaptation people too. The VRT relief is given at source, i.e. you don't pay it at all. The VAT relief is done by refund, i.e. you pay the VAT as part of the caost of the car and get a cheque back from Revenue, but again, some garages will facilitate this by letting you not pay the VAT and you passing the VAT cheque back in to them when it comes. Not sure if that part is strictly the way they are supposed to do it, but some do.
The VAT on the adaptation is also refundable by the way as part of the VAT claim. It's important that the documentation for that is marked PAID before it goes to Revenue.
Anther thing, the car seat can usually be transferred from vehicle to vehicle when changing the car, as long as the vehicles are reasonably similar. You basically keep the original new car seat which came with the vehicle. Then on changing in a couple of years, the adapted seat is transferred to the new one and the original seat put back into the old one. The relief on the replacement vehicle depends then on the original cost of the adapted seat AND the aadditional cost of changing it to the next vehicle together coming to 10% of the pre-tax cost of the next vehicle. So basically once you outlay on the seat, it can go forward but for the changeover cost. This may be a bit ahead given that they haven't got the first one yet but is important to know as I know of cases which fell through not meeting that replacement cost test.
Lastly, a good source is the
Disabled Drivers Association of Ireland. Who could also help with the EU parking permit.