Apologies for flooding this thread with this subject!
I have indeed recreated yesterdays scene this afternoon with surpising results. No UV filter - however I believe there was no difference in image quality what so ever. I did place the kid in front of the sun, so, no artifacts - even tho it did show up again without the UV filter in other shots.
As you can see from the attachments, I was quite a bit closer, with a much slower shutter speed (1/60) and ISO (200). But, what I did change, was to shoot in bursts of 5 and was able to choose the sharpest one. I found that for every one out of 5 bursts, there was one clear winner - all hand held with IS obviously.