mines the same and i have a smart meter on and graphing its usage and i can tell you one thing for sure!
it eats electric like theres no tomorrow.
The only thing you can do to reduce its habits are switch it to summer mode and get hot water only and switch it to spring/aut to get heating and water but this (spring)setting is the killer along with winter mode.
i switched it to summer and turned the fan off on the control unit!(3rd button down left side)summer switch is top button left side!
with this setting you will see a big decrease in usage but alas you have no heat in the rooms and your water will get cold unless you switch the fan on (setting fan 2 speed)for 20/30 mins+ before you want a bath!
this way you only use it when you want to!(still canes the electric though when you engage the fan to heat the water but i guess its not on all the time.
you may have to remove the temp limiter aswell if the temp for the water doesnt climb enough(find service menu settings)
engage the limit after your bath.
so far though i havnt seen any problem leaving it off but each seems differant!
no matter what you do this boiler will screw you out of your money and worse if like mine and it goes wrong for 3 months+ and engages the immersion 24/7 while waiting for a tech to come out to fix it which still isnt done yet!(all sorts of issues internally)
£600 in three months(now over £800)£133.25 in two weeks!!!!
beware this boiler as when i goes wrong it will shock you and considering we are housing association the bill is beyond our means and as it was faulty when the debt happend im hoping the HA will help us out (using readings from my smart meter and graphs to show with and without the heater and during its OFF phases(its faulty phase)
it would shock you seeing the graph when its faulty and almost as bad runnin