Why Defy only get 4 Stars

We have several Defy appliances, 2x Fridge/freezers, Dishwasher, Tumble Dryer, and a DHD394 Hob. One of the reasons for buying Defy is that they have a solid spares system. When we had a problem with a fridge door, no problem spares were available. Same story with the tumble dryer when the belt broke. Similar with the Dishwasher, new spray arm and runner stops, no problem. All these appliances are more than 10 years old, and I would expect some wearing parts to be replaced. Then we come to the Hob. The newest appliance. The hob stopped working, and I realised that there was a fault on the motherboard. I called in an appliance repair Company, who replaced the motherboard. All was fine for six weeks, when the same problem recurred. The hob has just been re-repaired and is once again working fine. I asked the Technician why he had not returned the faulty board to Defy. His answer, "Defy do not guarantee electronic parts" That is why Defy only gets 4 stars. Will I buy any Defy product with electronics, I will seriously look at all rival manufacturers first. Surely Defy offers a guarantee on their electronic parts in line with the Consumer Protection Act? Tell me that the Technician is misinformed and Defy is straight to 5 Stars.