Captain John Fox Burgoyne is recorded as blowing the bridge at Benevente in the presence of the enemy and also the bridge over the Elsa at Castro Gonsalvo.
The Royal Engineer Journal for 1930 has an article on the Engineers and the retreat. "in Sir John Moore's retreat, when all attempts to blow up stone bridges to...."
According to Christopher Duffy Corunna the engineers had problems blowing the stone bridges (failed at Betanzos) but blew up the one at Burgo. The RE were with Edward Paget's rear guard.
Perhaps History of the Corps of Royal Engineers Major General Whitworth Porter RE. 2 volumes Longmans & Co. 1899 will have details?