It can be I said "Having by-pass valves with condensing boilers is not
recommended and should be avoided". Sound advice. There are many ways to
get around this. A heat bank/thermal store. Replace the internal pump
with
a Grundfos Alpha. Install an intermediate buffer store - a 40 litre
cylinder
heated by the boiler, with a fixed speed pump between boiler and pump and
Grundfoss Alpha between the rads and buffer cylinder, etc, etc.

The DIYers know all the answers don't they.

All these solutions are a bit OTT when you could just install the
manufacturer's recommended auto bypass valve, assuming they haven't already
incorporated one inside the case.

Are you seriously recommending:

a) Invalidating the warranty by replacing the internal pump.
b) Spending hundreds of pounds (and lots of space) on completely unnecessary
intermediate thermal transfer when you could just set the auto bypass high
and not having it pass unless unnecessary?

You're really quite barking.

Christian.