I heard some bloke at an energy efficiency company advising people to
turn their boiler control UP (leaving their room and cylinder stats
alone). ie: If the switch on the boiler went 1-6 and it was at 3, turn
it to 4 or 4.5.

He said this is because the boiler gets hotter quicker, heats the tank
quicker, and reduces cycling. Thus saving energy. But won't this mess
with the condensing point of a condensing boiler?

His argument is: tank calls for heat, boiler and pump start, boiler
reaches temp and turns off, tank still wants heat, pump still goes,
primary side water and boiler cool, hence the waste.

It all just doesn't quite sound right, somehow!