[2] On four separate occasions, between 1804 and 1810, he was deputed by the states and Royal Court of Guernsey to represent them in London, in respect of certain measures affecting the trade and ancient privileges of the island.
[2] In 1821, following the death of Sir Peter de Havilland, he was appointed Bailiff, or chief magistrate, of the island, and soon after was again despatched to London, to protest, which he did with success, against the extension to Guernsey of the new law prohibiting the import of corn until the price should reach 80s.
In 1815 Guernsey had had no roads, there was danger of the sea overflowing large tracts of land, there was little or no trade, little or no disposable revenue and no prospect of employment for the poor.
The suggestion was put forward that the States should take advantage of their ancient privilege and print their own notes to finance various projects to remedy the situation.
Other projects, including the widening of the streets of St. Peter Port; the reconstruction of some of its buildings, new roads and new public works of many kinds, were financed in this way over a period of twenty years.
In 1832, when the right of the inhabitants to be tried in their own courts was menaced by a proposed extension of the power of writs of habeas corpus to the island, Brock and Mr. Charles de Jersey, king's procureur, were sent to London to oppose the measure, and did so with success.
Three years later Brock was once more despatched to London at the head of a deputation to protest against the proposed deprivation of the Channel Islands of their right of exporting corn into England free of duty.