I have an Ergo and am using it on #2. We carried DS in it up until DD was big enough. I live in it, love it and would buy another in a heartbeat. My kids are big, and a little taller than average. My daughter is a backarcher, and I haven’t had any problems yet. I don’t find it too short for their bodies, or hard on my knees. I am old, and a former figure skater, so my knees are in pretty bad shape :-(
I do not put newborns in there- I heard that the converter doesn’t work well, and it looks wonky to me. Perhaps they’ve improved on it in the past 3 years, but I used a woven wrap until they were big enough for the Ergo….like the wraps, but there is a learning curve, and if you use the car a lot (and are wrapping up in cold parking lots) it becomes a drag very quickly.
If you do go the Ergo route, they are significantly cheaper in the US. I think there are some people on this forum who are there, and might be willing to have it delivered to them, and ship it to you at cost and with the appropriate language on the customs form (value £1, used property of addressee) to avoid those delightful duty charges.
However, I have seen some “locally grown” equivalents that also look good. I think FairyCakes makes some good suggestions, and it sounds like she has access to a lot of different models (lucky her!). You may want to check out slingmeet and see if there’s a shop near you, or better yet, a sling library, where you can try a bunch. Kind of hard with a bump, but better than nothing.
Good luck and enjoy your search!