no stop valve on water supply to bathrooms

so i had to change the inlet valves on my toilets. have one in the ensuite upstairs and one in the bathroom downstairs. however there doesn't appear to be any stop valve on the pipes feeding these loos (or the taps for that matter). i had to drain the water tank to below the outlet levels before the water would stop running and i could change the valves. i turned off the cold water inlet into the house and there is another pipe in the hotpress labelled "to cold water taps in ensuite and bathroom" but turning that off didn't stop the water flowing to the taps or the loos anywhere. it was still draining from the water tank.

there wasn't anything i could turn off on the pipes leaving the water tank in the attic either.

is it normal not to have a stop valve supplying the taps and the loos? the house was built in 2011 and i'm wondering if the plumber messed up? surely it can't be right that i have to drain the water tank to change the loo valves or even the tap valves (other than the kitchen sink). or is that normal practice?