Hi mariedj, I stumbled across your post when doing a search for music to play to my baby in the womb last week, and have been thinking about it since then so thought I'd reply.
You are right that there probably will be hardly any other kids there. I went to the Saturday of Lovebox last year and was actually quite dismayed to see some little kiddies there - even some very teeny tiny babies in prams. It was so loud and inevitably trashy into the afternoon and more so into the evening. Some kids had their big headphones on to block the music out, but not all did. It's really not a family-friendly festival at all, with nothing geared towards children - in fact they had a few fun fair rides, but all adult versions so the few kids who were there could only look on longingly.
One of the worst things that I saw was someone being sick on the side of the dancefloor (close to where a number of people had been weeing - I guess it must have seemed the kind of place that looked discreet after a few drinks/puffs/snorts/whatever!) and soon afterwards a little kid came and starting playing in the exact same spot!
Maybe I'm just past the whole trashy festival experience, but I found the whole thing gross and took myself home before my DP and friends.
There are much better festivals to take your DD to - I am looking forward to doing Camp Bestival again, but with kiddies in a few years time. I really enjoyed that a couple of years ago and I think the presence of all the kiddies made everyone so much better behaved, which was soooo much better than other festivals where there seems to be someone puking or weeing wherever you look!
Hope this is helpful rather than hugely negative!