Hi twinmam - thumbwitch saw your post and asked if I'd have a look because she has this idea that I know what I'm talking about .
I am a chiropractor (in Canada, though so, sadly, not much hands-on use to you) and I see quite a few mums and babies in my practice. IMHO, most babies do funny things with their legs when they're learning to walk. Sort of the gamut from what you're describing, to walking on tippy-toes for a few weeks, to waddling like penguins. In just about all cases I've seen, they stop doing whatever it is when they get to be comfortable walking and are solid on their feet. So if I were seeing her professionally, there are a few things I would check, but otherwise I'd let her get on with it and observe for a few weeks to see if she stops on her own once she's willing to let go of your hand.
What's worth checking out is whether everything's ok with her hips. When a foot is seen to turn out, the problem is most often not actually the foot (which is the end of the line, so to speak) but the hip, where the entire leg starts, IYSWIM. What you can do when you next change her nappy is
1 - lie her on her side and sort of poke around in the outside-to-middle of the left buttock/ hip and see if the muscles seem very tight to you. Check the other side to compare. This can be a bit difficult with a squirming toddler of course and even more if you're not used to feeling and noticing muscle tightness and texture. But - if you really feel a difference in muscle tension between the left and the right, that may be what's causing the leg/ foot to turn out. The muscle group in that area is called the "external rotators" and they turn the leg out (especially a muscle called the piriformis) and when they're abnormally tight, they keep the leg in a turned-out position. Treatment would be massage or myofascial release (a deep form of massage) of those muscles - best done by a massage therapist, physiotherapist or chiropractor who specializes in Active Release Technique. To find a chiro who does A.R.T. in your area, go to Active Release.com and click on "Find A Provider". I don't know if you're anywhere near Bournemouth, but you could also ring Anglo-European Chiropractic College and ask for a recommendation for practitioners in your area who specialize in treating toddlers.
2 - if the above seems ok to you, and she's walking cofidently but still turns her foot out, I'd take her to an orthopedist to have the foot/ ankle structure checked out, or the hip joint. Babies can have something called "developmental dysplasia of the hip" where the hip socket and head of the thigh bone don't form correctly. Usually diagnosed by x-ray.
It's likely to be something she'll outgrow, though, so for now, don't stress too much.
Hope this helps.