There's an alarm installer in Dublin with three capital letters as their business name.
I got a product installed by them and it would work sometimes, and not other times. It's stopped working entirely since March and they've decided to just ignore me regarding a refund, repair or replacement. They were happy enough taking ?300 to install it.
I'd advise anyone to stay away from them, and I'll be seeing them in small claims court.
When I worked with VW I used a chap called Andy in AAA autos. Tidy work and should be able to offer a selection of alarms. Never any problems in all the cars he installed alarms and parking sensors etc in. All his alarms came with a thatcham certificate.