The Barclay brothers plan to take their challenge to Sark's constitution to the European Court of Human Rights after losing an appeal in the Supreme Court.
Advocate Gordon Dawes, who represents the billionaire twins, said while they respected the court's ruling, they felt they must follow their judgement.
The brothers argue reforms do not go far enough because two of the members of Sark's government are not elected.
Elected conseiller Charles Maitland welcomed the court's decision.
He said the reforms to the constitution should survive further challenges.
Mr Maitland, the chairman of Chief Pleas general purposes and advisory committee, said: "I'm quite pleased as we've had a great deal of reform already and I don't think there is need for any more.
"We must be the most democratic island in the world with 28 representatives for only 600 people including babies and children. You can't ask for much more really."
Sir David and Frederick Barclay believe the offices of seigneur and seneschal to be contrary to the European Convention on Human Rights.
Advocate Dawes said: "Their concern is that the government of Sark should be put on a proper footing.
"They are concerned that here you have a small but very powerful assembly of 28 elected members but still with two unelected members holding considerable powers within that body."
Mr Maitland said: "They don't form a political role any more and now the politics are up to the 28 elected conseillers so I really don't know what all the fuss is about.
"It's an historical role they've both done for a great many years going back through the mists of time really. Let's leave it at that."
Advocate Dawes said his clients' business interests in Sark should be unaffected by the latest ruling.