Replaced like for like flush valve in Ideal Standard cistern, but do not seem to get more than half filled, giving insufficient water for flushing, even with float (OK) at maximum. As existing valve was already fitted when renting the property have no idea whether it was correct for the cistern. Where can I obtain dimensions or full description of flush valve which should be fitted. Fed up with keep using double flushes and buckets to clear. Drains AOK from adjoining bathroom toilet.