I suck at DIY so any help here would be much appreciated
We've recently noticed that the water level in our toilet is really, really low. The cistern seems to be completely fine, and flushing works absolutely fine. When you flush, the water level in the toilet bowl fills up to the proper level, but slowly drains away and 10 mins or so later it's really low again. I thought there may be a leak but surely if there was the water would completely drain away leaving the toilet empty - it doesn't do this, it gets down to a low level but then stays there.
Does anyone have any ideas? Any checks I could do before I pay a plumber to come out and have a look? Could it be related to maybe low water pressure in the area or something (not that I've heard there is)?