Help I've rented a 1920s house with an old close coupled double trap syphonic / siphonic toilet (Armitage Shanks). The problem is that whenever it is flushed, the level rises in the pan to the brim... to almost overflowing (...a really disconcerting habit for the unaware.). then just in time it the flushes away fully followed by a clean refill to an above average water level (- a level that is simply too high for even the average endowed male on a sit-down job! Wet dangly bits - not nice). The drains were initially suspected but have been checked and declared clear. It looks like its been doing it for years judging by the calcium ring at the above average water level. Anyone seen this behaviour before? Is this a feature or common fault with such toilets? Any solutions (other than changing the toilet assy)?