The following is the entry for William Allen in William O'Byrnes 1849 'Naval Biographical Dictionary'.
ALLEN. (Captain, 1842, f-p., 14; h-p., 28.)William Allen entered the Navy, 2 Oct. 1805, as Fst.-cl. Vol., on board the Standard 64, Capt. Thos. Harvey, with whom he continued to serve, in the same ship and the Majestic 74, on the Mediterranean and Baltic stations, until Feb. 1810. He was present as Midshipman, while in the Standard, at the passage of the Dardanells, in Feb. 1807, and on 26 March, 1808, assisted at the capture, in the Adriatic, of the Italian brig of war Friedland, of 16 guns. On leaving the Majestic, Mr. Allen sailed in the Leda 36, Capt. Geo. Sayer, for the East Indies, where he co-operated in the reduction of Java in Aug. 1811, and took part in a vigorous and successful attack on the piratical settlement of Sambas, in Borneo, 28 June, 1813. He obtained his first commission 2 March, 1815, and after intermediately officiating as Lieutenant pro tem, of the Hesper 18, Capt. Wm. Everard, returned to England in the following September. Being next appointed, 12 Nov. 1834, to the William and Mary yacht, Capt. Sir Sam. Warren, he served in that vessel until promoted to the rank of Commander, 20 June, 1836. Joining, 10 Oct. 1840, the Wilberforce steamer, Capt. Allen subsequently attended a disastrous expedition to the Niger, whence he returned towards the close of 1842. He has since been on half-pay. His Post-commission bears date 31 Jan. 1842.