Hi. DD1 has hypermobility, and is considered a 9 on the Beighton Scale, so VERY bendy. She didn't really start to walk until around 16-17 months and was very unsteady. She bent inwards really badly at her ankles, and I was very aware of how she just couldn't keep up with the other toddlers.
My GP was great, and got us referred to our nearest Child Development Centre, (they are all around the country - check on Google).
She saw specialist physios who ONLY deal with children, and was fitted out with shaped insoles, which corrected her feet, - she wore these until she was 3.
We were given a lot of guidance by the physios, basicly, the main aim was to get her as strong as possible, so perhaps you could try the following;
Encourage her to climb stairs, (under supervision, of course! Build "assault" courses with cushions, and get her scrambling. When possible, put interesting things slightly out of her reach, so she has to reach up to get them (stretching the ankles, calves and arches).
Practise walking when you can - (she sounds keen!), but try to avoid holding her arms above her head. Doing that pulls the pelvis out of alignment, and prevents a proper foot strike. It's much better to encourage her to support herself without raising her arms up.DD used to walk around holding one end of a folding umbrella, while I held the other end!
Try letting her walk around pushing the buggy when you go out.
Get some reins, so you can limit falls when she's walking.
It's also important to develop hand strength, so lots of sand play, dough-squeezing etc is helpful.
Finally, I would just like to reassure you that this is really quite a common condition, and is the main cause for late walking, - you're certainly not alone.
DD1 is 7 now, and really has no physical problems, other than being a rather ungainly runner! We were warned that she might struggle with writing/pen-control - in fact, she is extremely good. We were told she might tire easily, - she is a ball of energy, can walk for miles, and regularly swims 10 lengths+ with ease. We were warned to avoid ballet and gymnastics, as these would encourage her to over-stretch.
Yes, some children can be badly affected, and I'm not a complete ostrich, I know that her condition could change, but as she has clearly inherited this from me,(it always runs in families - I was never diagnosed as a child), and I have reached the grand age of 45 with no problems, I'm hoping for the best!