Go to your nearest plumbing shop tell them your after two tap connectors from 22mm taps to 15mm feed pipes or flexi fits if they do ones 22 x 15mm or they may say the only way is 22mm tap connectors then 22mm pipe with a 22 x15mm reducers on each pipe. what ever, it can be done. If flexi fits don't kink the pipe run smooth curved bend easy to fit some have check valves in the fitting.
Bob
May 2009