Hi CGlass, give The Children's Osteopath Clinic in Wandsworth a call - we went there with our baby girl for 6 sessions - following reflux and lactose intolerance - and also a problem with her not being able to switch off to go to sleep - they diagnosed a problem with the right side of her neck, it was tight and she never looked or turned her head that way - apparently its the nerve that helps our bodies switch off and get ready for sleep - but she couldn't do it because of the tightness.
After only 2 sessions there were huge improvements in her neck mobility and after 3 weeks she began to sleep in the daytime (before she would go 9hours without sleep at 6weeks old!!??!)
They are a charity so you just pay what you can afford per session (they recommended £35 a session)
Here is the website -
http://occ.uk.com/
they are just off putney bridge road in Wandsworth
Hope it can help x