Just moved house and the second toilet did not flush well. Decided to replace all.of the flushing mechanisms as the intake and overflow pipes looked very old and green. However could not remove the overflow pipe. Completely stuck, used wd40 but not budging. Then managed to chip a bit of the outside of the cistern around the hole for the overflow. So it seems sensible to change the cistern. The toilet seems old. However, it is not as easy to get one as I thought. Some of them are button flush which is fine but am now out of my depth in terms of understanding what to get. I've changed the syphon etc before do Happy to do that but not sure how to proceed with new cistern, old pan. Any thoughts? Thanks