They are required so I guess you could, at least theoretically, get fined for not having them... particularly if your standing or plying for hire... obviously they have no relevance to private hire (phone, wireless, app, etc) jobs as county restrictions don't apply to the same. Minister Kelly said we could buy them in any hardware store but my own local hardware doesn't stock them and when I enquired had no intention of stocking them going forward. If you can't find a hardware store that does stock them I'd suggest ordering them from NTA and keeping a copy of the receipt / call reference number in the car until you receive them. That combined with appropriate dashboard ID cards ought to satisfy any enforcement official. As Jill (2nd in command, CTR back then) told me years ago, they don't habitually reach for the ticket book i.e. they apply a degree of common sense.