I've just taken delivery of a Grohe Bauedge basin mixer tap which came with tails preinstalled. The ends of the tails have female 3/8" connectors on them along with the appropriate rubber washers, but neither Screwfix not Toolstation seem to sell 15mm copper to 3/8" male connectors. Does anyone on here know where I can find such beasts? Ideally they should be solderable onto the 15mm copper pipes in the undersink cupboard, but pushfit would also do. Many thanks in advance for any pointers/guidance.