Unfortunately, they have fallen foul of another body with its own, equally strict, set of rules: Nuneaton and Bedworth Borough Council and Section 97 of the 1985 Housing Act.
For Brother Luke - real name Denis Keegan - has set up his chapel in the red-brick coalhouse on the first-floor landing outside his flat on the Blackatree Estate in Nuneaton, Warwickshire.
The neighbours have complained about the chanting, and Brother Luke did not get change-of-use permission.
'We do not consider this to be an improvement,' said the council's housing manager, John Dolman.
Brother Luke, 35 and unemployed, views it as persecutiuon on religious grounds. 'This chapel has been consecrated. It's not to be closed down at all,' he said. 'I shall be fighting it all the way. I've not done any harm or knocked any walls down. Anyway, I don't use coal or solid fuel. I've got a gas fire.'
The housing department is taking the accusation seriously: 'We shall investigate his allegations about the way we've treated this case,' said Mr Dolman. 'We do have an equal opportunities policy.'
Brother Luke's spiritual journey to Greek Orthodoxy has taken a roundabout route. The son of an Irish mother and a Pakistani father, he was brought up by nuns at Coleshill, near Birmingham, but became disillusioned with Roman Catholicism. After brief flirtations with the Church of England and Hare Krishna, he discovered what he calls 'the true faith' three months ago.
On Christmas Eve, he and his small band of supporters will travel 10 miles down the road in a hired minibus to the Greek Orthodox church in Rugby for his official confirmation.
Brother Luke dons a long robe of brown Crimplene to lead worship in the former coalhouse. 'About five of us can get in here at a push,' he said.
What particularly appeals to him is the veneration bestowed on icons of the sort now installed there. Space has been further restricted by the installation of two shelves bearing a Bible, a prayer book, the Divine Litany of St John Chrysostom, an incense burner and part of the cloth that covered the body of St Edward the Martyr, encased in marble.
'I got it from the Orthodox monastery,' he confides. That's the Orthodox monastery in Essex, he adds.
Has he ever been to Greece? 'No, but I'm saving up to go.'