The onus is on the seller to get the vehicle out of their name. I unfortunately had to scrap my car. Insurance company paid and recommended a scrap dealer. I found one who offered a better price, filled out an RF105 (change of ownership to a motor dealer form) available from Motor Tax Offices, laughingly declined scrap dealers offer to forward this to Change of Ownership in Shannon on my behalf, sent it off myself. Car is now back on road with a new private owner but I am free of any responsibility. If Quinn Direct took your car or authorised a scrap dealer to do so, YOU have to fill in that RF105 to the dealer, remembering to put down original date of sale and not "todays" date. Send it to Shannon. Shannon will accept an affidavit, they have a particular form, but it is a lot of trouble and expense. Once Shannon receive the RF105, give them a couple of days to make the change, then get a certified details letter from your Motor Tax Office. They will need proof of I.D. such as your driving licence. The letter will say the date you sold it and the date you ceased to be the owner, the latter being the date Shannon receive the RF105 from you. The guards usually accept this and have their own methods of finding out who current owner is.
To keep the chain, seller should fill in VLC with QUinn Direct, send to Shannon, let Quinn Direct worry about it then.