The Beco Soleil is a sturdy padded carrier with a waistband and with crossable straps that can be worn rucksack style. It suits babies from about six months upwards but can be used with a separate insert for a younger baby.
It will allow hip and back carries.
It is EN13209-2 Soft Carriers Certified
Here is a video for how to put the Beco Soleil on with crossable straps
There are more videos and photo tutorials listed on the Carrying Matters website.
The Sheffield Sling Surgery website is here - full of useful information about safety, all sorts of articles about warm/cold weather carrying. knee to knee support, big kid carrying and so on
Facebook page is here and the online support group the Virtual Sling Surgery is here