Hmm interesting to see the responses to this - my DC2 did this when first started walking, only the right foot pointed out at right angles. He did it more when someone was holding his hand. Now 2 months later he doesn't do it very much at all but I was constantly wondering whether he ought to be seen.
We had/have one like this - your hv will prob refer you to get tests. Dd on VIt D related treatment and physio now, worth getting checked out. But don't panic, they've never thought it was anything much.