I bought a car privately through an ad on donedeal a number of years back. After agreeing a price,.signing over the logbook transfer and paying the man for the car, I tried to ring my insurance company on-the-spot to transfer my insurance so i could legally drive it home but there was absolutely no mobile phone coverage. I opted to take a chance on driving it a few miles up the road until I had phone reception, but as luck would have it, I hit a checkpoint. Naturally, the Garda was fairly suspicious as I initially couldn't find the electric window button to talk to him, on further questioning nor could I tell him the original owner's name or show him any documentation whatsoever that I was after buying it. Nor did I have my licence. I couldn't call up the original advert online there-and-then either as I had no signal.
To make a long story short he told me I was getting a summons for no insurance unless I could prove I was insured. A week or so later I called to him by requesting an appointment with him at the garda station. I brought my licence, tax, NCT and insurance details for the vehicle I was actually insured on that day - not the one I bought that day. He looked through it and said he'd ring my insurance company himself, explain what had happened, and ask if they'd be prepared to cover me for the date in question. I wasn't there when he made the phonecall so I didn't actually hear it, but he came back a few mins later and said it's sorted and my insurance company, who I'm with almost 20 years, had said I was covered on the date.
I would approach the Garda, bring as much paperwork as you can.It's worth a shot.