You have the Rolls Royce of boilers btw. Should last 20years +.
Would agree that Vaillant is the best of the main brand bunch, but certainly not the rolls royce of boilers.
After many years of being a solid Vaillant installer, they have peed me once too often, so unless a customer specifically asks for one, I will not specify them any more. I only fit better quality than them now, with direct and proper help/support if rarely needed.