I can thoroughly recommend it. We took ds2 for colic at around the same age...
The first session was a bit odd - for one I couldn't see that he was doing anything, and for another ds2 screamed and screamed throughout and I had to sit on my hands and tell myself that it was all for the good! Horrible! The CO told me that the bones of his skull were all squished so it would have been painful for him to lie flat, and the ribs near the bottom were quite tight.
Second session he almost dosed off during the session and was much more comfy. His symptoms were worse for 24hrs, then great improvement (but only lasted 2 days) - apparently very common. Third session the "good" period lasted much longer. We needed four sessions in total.
I wouldn't say that the cranial osteopathy was so much a cure, as a way to enable other methods to help. After the second session, I was able to soothe ds2 in other ways (like with white noise, rocking, cuddles etc) which just weren't effective at all before. HUGE improvement and made a huge difference to ds2's early life, and I personally believe it was worth every penny.
I don't know any particular CO's in your area, so I hope you get other recommendations. Otherwise, it's worth asking around (your HV, GP, at mum and baby groups...) asking particularly for a registered CO with extensive experience with babies. Do bear in mind that it's not a quick fix and it may take up to 4 sessions to see results, so do budget that in.
Hope that helps