I can't offer any advice, but we are in a similar position to you. Maddie, who is nearly seven, needs hers emptying regularly. We usually manage three months at a stretch but they are sometimes infected. One vet has said they are misaligned, last week the vet said the tubes were so narrow they couldn't empty naturally. She mentioned flushing but not really suggested it for Maddie. I take it using high fibre supplements, like us, hasn't helped?