Toilet will not flush !!

My loo has suddenly decided it will not flush, I thought initially it was the plastic link rod that attaches to the handle and lifts the syphon plunger but that is all ok. In fact looking inside the cistern all looks ok. I adjusted the ball value so as to introduce more water into the system, and the loo flushed a couple of times then gave up the ghost. I understand that it may be the syphon washer or diaphram (?) is this an easy fix ??. The loo is a close coupled so what needs to be done to fix ?? - a new diaphram or a new inner gubbins - any help much appreciated 'cos i'm having to use a bucket of water to flush and the missus ain't all that pleased - she is threatening to withold my Christmas present and other marital rights and priviledges, I 'm not too fussed about my marital rights, but don't want to miss out on my Crimbo pressie All help much appreciated

new syphon 6 quid . empty cistern and remove turn it over and undo big nut .replace washer when refitting cistern

agree with above, since a new diaphram costs a couple of quid, and you have to take the whole syphon out to get to it anyway