Although I have the Campagnolo peanut butter wrench (and it is a lovely thing) in my regular tools there is an Icetoolz tool with a 15mm thin wall socket at one end and a plain 15mm spanner at the other (which is handy for pedals). It is also rubber covered so it is kind to hands and cranks.
Put ‘icetoolz 34a2’ into ebay, Google or Amazon.