Hi, Having purchased a 1988 Abbey Somerset one week ago and being completely new to caravans and caravanning I was told by the previous owner that I need a pipe / filter to connect the water supply from an Aqua roll. I've seen several on Ebay that look similar to the connection on the side of my van, but the sellers have warned me that there are lots of different types. The only problem is that I don't know the number of the correct type. Please could someone help before I waste money buying the wrong one?