Thanks for all your comments so far.
Yes the early Celtic church did incorporate a lot of paganism into it - but then that is hardly surprising given when and where it was founded, and it isn't unique in Christianity by any means.
The modern Celtic movement, as exemplifed by the Iona Community or the Community of Aidan and Hilda, for example, is certainly very Christian - in fact, many of its most well-known adherents are ordained priests, such as David Adam, John Bell and Ray Simpson. Their religious communities are based on the old Celtic monasteries that were places where whole families lived, rather than celibates of one sex or another. The modern communities reflect this, and anyone can join if they are committed enough, and live their life according to vows that fit in with their daily life.
There are also some really beautiful new Celtic liturgies being produced .
I found Celtic Christianity at a time when I was really struggling, I've always been a Christian and although I knew I needed to find a way of celebrating my faith I never thought I'd find anywhere. The two big things for me were discovering a type of Christianity that is in awe of the natural world, and one where women are treated as equal to men. Through studying it I became aware of the Celtic Christian way of rooting faith where you are, and joined my local Anglican church. Sometimes it is a struggle, given the way the church tears itself apart over non-issues like sexuality and gender, but it is where I belong, and I can weave it into a Celtic pattern.