Did you select the bulbs yourself or did Halfords get them off the shelf for you? I think I googled the bulb type and then went in and got them myself and fortunately solved the problem. I have had a similar issue with the car, halford and front wiper blades, they sold us the wrong ones, tried to fit them at home and the connection was incorrect, again googled and exchanged for the correct type of blade. Ironically Halfords sold us their own brand at about £5 more than bosh which were the correct blades. After 2 bad experiences I wouldn’t trust them.