I am repairing a broken rainwater drain. It is clay, fed by a clay bend, in turn fed by a 4-inch external diameter PVC downpipe from the gutter. I bought a rubber adaptor to bridge from the bend to the damaged pipe. It fits, but only just, because of alignment. I was thinking of a Plan-B: add a PVC bend to the downpipe, then PVC into the drain. However, all the parts in my system seem to be museum pieces. Does anybody know whether it is still possible to get a coupling that fits 4-inch external PVC?