Seperate heating & hot water systems?

[LiveInABox]

I've just moved into a house which appears to have central heating running from what looks like a relatively new combi boiler in the garage.
However the hot water does not run from that boiler (there is a sticker on the boiler saying that it doesn't operate the hot water). That seems to be run from two hot water tanks and a cold water tank all in the loft, and controlled by a simple on/off switch in the kitchen.

There are currently two bathrooms in the property both with electric showers and it needs to serve 3 adults and 2 kids. We'd like to add an ensuite shower room to our bedroom in the near future.
Is the current set up going to work? Is it worth getting everything moved over to the combi boiler before we install the ensuite? Any other suggestions/considerations?

Thanks in advance, I'm totally clueless about things like this!

When you say "tanks" do you mean cylinders?

What colour and size are they?

Why does the boiler appear to be a combi? Does it fire up every time you turn on a hot tap?

Hi PigletJohn, I was hoping you'd be along

In the loft there are two black plastic boxes, open at the top with water in. One is bigger than the other.
There's also what I think is the cold water tank, but I can hardly see it, it's right under the eaves and wrapped in insulation.

The boiler in the garage doesn't fire up when got water is run, there's a sticker over the hot water controls on the boiler which says that it doesn't control the hot water, only the heating. I assumed it was a combi but that's not based on anything really!! How would I know?

examples of cylinders

examples of tanks

if you mean a sticker on the timer, combi boilers do not usually control the HW with a timer. Only the CH is usually timer controlled. The sticker may refer only to the timer.

Stand by the boiler and get someone to run a hot tap. Preferably to run a bath or shower since some boilers hold a reserve. Does the boiler fire? Then to turn it off. Does the boiler stop?

there is a faint chance that your hot tapwater is heated electrically (energy from electricity costs about three times as much as energy from gas).

Turn off the hot water switch. Go and look at the electricity meter. If it is a digital one, time the gaps between flashes. Write down the meter reading. Wait until the hot water runs out. Look at the meter again. Turn on the hot water switch. Write down the reading and time the flashes. Go and look at it again after 1 hour and after 6 hours. If it uses a huge amount more electricity while it is heating your water store, then you probably have a cylinder or a thermal store. It will be expensive to run.