Having a feel, there's a slot all the way around the bowl (I was expecting holes). We're in a hard water area, but I can't find any limescale blockages. Toilet has been cleaned with Toilet Duck equivalent which should keep down the limescale?
A few years ago I put a Hippo water saver in it. Taking it out it's better, but still the front 90 degrees aren't flushed.
At the hole at the back where the water emerges into the bowl, the hole seems to have an irregularly shaped plastic stick in it, maybe 1cm wide that goes back towards the cistern junction. I'm guessing that's what divides the water around the two sides rather than going straight down. The stick is loose - I can jiggle it and turn it around with my hand - but I can't remove it because I'd have to take off the cistern to get access. It doesn't feel like it has a naturally 'right' way to fit.
Should this bit of plastic be there, and if so is there a way to adjust it? Or what else might be causing the uneven flush?
Thanks Theo