If you have any issues with your kitchen appliances (hob, oven, cooker hood, dishwasher, fridge freezer), boiler, cylinder, or solar panels (if applicable), you should contact the manufacturer direct quoting your serial number, as they will only respond directly to you as the customer.
Upon completion you will find all of the user manuals and instructions for your new appliances, usually located together in the kitchen.
Each manual will detail the manufacturer of your appliance and will provide information about how to register your appliance in order to take advantage of the 2-year warranty period. Most manufacturers will give you the option to do this via post or to go to their website and register your appliance online.