This looks like the app rather than the IHD itself.
Does your IHD look like this?
If it does, you need to find that 'usage now' statistic. You can get this by pressing the area arrowed until you get to 'usage now'. First thing in the morning look at the usage now number from the IHD before turning on any appliances and hot water and central heating (other than those that are always turned on). You can get a 'rough' idea of daily 'always on' by realising that if your 'usage now' was say 100W, than in 1 hour you would use 0.1kWh (at the same draw) and in 24 hours you would use 2.4kWh as your 'always on' electricity usage.
From your March figure I see it says 185kWh for 'always on' equivalent to just shy of 6kWh per day. If this is indeed the case then I'd expect to see the 'usage now' figure from your IHD to be in the region of 250W (24/7) i.e. 0.25kW consumed every hour of every day for these 'always on' items.
Confirmation of what your IHD says last thing at night (after all appliances turned off) and first thing in the morning (before any appliances are turned on) would be helpful to ascertain if there is a problem or whether the app is just giving you false information.