I guess D.A my argument is not with the lack of guarantee it's more the way it's printed, but I guess that's probably par for the course with any manufacturer they are hardly going to highlight their negative points.
Buy a Kidd oil boiler. One of their engineers who services them was on here singing their praises a few days ago and recommending people buy them. Only problem is they ain't made anymore.
i would avoid a Worcester bosch in a loft space as the lack of pressure/water sensor means being at the top of the system it will dry fire with little loss of water. Generally tho i like worcesters and find there customer service the best. Vaillant are good boilers but have poor business morals selling installers customers details and trying everything to get out of warrantys. All manufacturers and models have issues, like cars or anything else really.
You're right. I just replaced a working standard system boiler for a Biasi white ellephant. It failed after only 5 months and Biasi simply are not interested. Sent me a call out bill for £95 and suspended my 5 year parts & labour warranty. Now only 14 months old My Biasi advance 35C is being taken out and replaced. I'm afraid I cannot recommend Biasi to anyone, even an enemy.