Reproduced below is the thoughtful response from the Chairman of B & H Liberal Democrats. (At present my constituency doesn't have a parliamentary candidate).
"Thank you for your question about Governmental faith advisors. Sorry for my late reply, but your question requires more than a simple answer.
The Liberal Democrats are commited to total freedom of religion and expression. We make judgements, including about religious tolerance, based on John Stewart Mill's 'Harm Principle', that everyone is free to do as they wish, so long as it does no harm to others. We do however appreciate the fact that, as a party commited to freedom, people, including decision makers, will often use religious grounds to justify decisions of conscience. It is up to other individuals and science to challenge those views. It would be illiberal to keep someone out of a decision making position soley because of their religious beliefs.
That said, I wish to point out that we are the only party commited to a fully secularised/democratised legislature, and we are actively pushing for the Lords Spiritual to lose their right to sit in the House of Lords and legislate without being elected (although we would welcome them running in an election to a democratic House of Lords).
Whilst we support efforts to harmonise and not demonise different communities, Liberal Democrats did question the value of faith advisors in Government roles and on the Government paycheck. Although they will have influence, they do not have power, and the government has just as many if not more scientific advisers. We would also point out that many Liberal Democrats are members of the British Humanist Society, and said John Denham recently highlighted in a speech that it was no longer fair for religions to monopolise charitable works, or the idea that you have to be a religious person to qualify as a 'good human being'. We support that sentiment, and any idea otherwise is abhorrent to Liberal Democrats.
As for the influence Lords Spiritual have, there are only 26 Bishops in the House of Lords, as opposed to 150 Crossbenchers who are appointed based on merit in service to different sections of public life such as academia, science, charity etc. 2009's 'Peer of the Year' was Professor Robert Winston, which perhaps displays that Scientists are maybe more prominent than Bishops in the House of Lords. Once again reaffirm that we support a fully elected Upper Chamber, so that no one section of society can have a stranglehold on priveleged office."