er...er...er a bit like dismissing a boiler because of a diverter valve that might go wrong or an automatic air vent? Or a cast iron OF boiler that is incredibly reliable but works at 50% efficiency? I dismiss it not because of reliability but safety.
I used bithermic heat exchanger boilers many times in the past and have seen the possibilities.
The thing is most boilers are installed into existing systems where the rads were designed for their certified temperature flow in of 75 degrees not 80. If the weather is extreme then that temperature is what the radiators will require to heat the property (many new build rads are sized to minimum also and most of those systems are certainly not weather comped even now).
If the heating system requires water at high temperature to keep the customer warm that is what it will be set to then you have the domestic hot water circuit at whatever temp the boiler stat is set to, there's a comparatively large quantity of it in the IG and it can be set to 90 degrees!!
A blending valve is not particularly cheap, certainly not low maintenance and adds rather to the number of moving parts.
The boiler has merits and is loved by many who know how to fit them, it will not always be nor operated by those who do not understand the possibilities.
Still the change from GAD to GAR last year will protect the installer giving separation between yourself and the customer if heaven forbid an untoward incident occurred. With the Directive the installers responsibility was to choose and install an appliance that could not endanger the end user by adjustment either deliberate or accidental. The GAR now places the responsibility for the same criteria on the manufacturer who must not place into the market in the EU any gas appliance that can be configured either deliberately or inadvertently to endanger the user. As this depends on the manufacturer's own risk assessment IG say it's an acceptable risk, I have a different opinion. I enjoyed your comment 'most users do not have the setpoint at a high level' these are not the people who are the concern.
There are installers who I respect enormously who fit almost nothing but IG and I have recommended old customers of mine to them knowing the boiler will be installed and the user instructed in the use. The electronics and control possibilities I'm told are exceptional but I would not want one in my own or a family members house particularly if children are present.
As for saving the planet, get real.
Tadlad's earlier post regarding hot water temperature control shows he does not understand the relevance.
Not going to get into a heated debate although you could mention that you work for a competitor but do you really still tell installers to set the flow temp to 80 degrees on Vokeras?
Most boilers I attend set up by quality installers have a flow temp of somewhere around 65/68 degrees. The days of an 11 degree delta went out when steamers were made compulsory and systems are specced on a max of 70 degree flow to ensure the return is low enough to condense.
How efficient are Vokeras when run at an 80 degree flow temp?