hi norman-to connect the two tap ends you will need a double 1/2" bsp fitting(or 3/4" if we are talking 3/4"-22mm)--to connect the tap end to a compression end you will need a 1/2" bsp/15mm compression fitting-if it is a push fit you will still need the 1/2"bsp/15mm comp fitting and a 3" length of copper in the compression to allow the push fit to connect-you could of coarse get a longer flexi up to 900mm is available easily--to connect to your tee you will have to come off it again with a short length of pipe
jrf
August 2008