For 1811 and 1812 the British Government awarded Portugal a grand total of £999,999 above the regular subsidy. This was at the urging of Wellington who wrote in 1810 about the distress of the Portuguese who had both followed the ancient Portuguese Laws on scorched earth tactics and who had been mercilessly plundered by the French.
The British people themselves also set up a fund which eventually totalled £85,000 and the money was allotted to the districts ravaged by the French such as Thomar, Guarda, Castello Branco, Pinhel, Coa, Coimbra, Pombal, etc. Lisbon District: Santarem, Obidos, Torres Vedras, Aruda, Villa Franca, and Leiria, Lamego, Crato, Aveito and Vizeu. The money was to go to General Relief, Orphans, Hospitals, Women and Children.
There is evidence that the area chosen for the scorched earth tactic was not laid barren as much as Wellington had hoped and had asked the Portuguese Regency to order and enforce. The Santarem area, just twenty miles back of the lines was not cleared out by the Portuguese and here the French found new sources of supply. But note that it is included in the relief effort as having been ravaged by the French.
In Ireland, they also set up a fund and donations of money and goods were accepted. Wellington wrote to Sir Charles Asgill, that cattle, oxen, etc. would be better than just sending money.
BTW, the British people also set up a fund to assist the sufferers in Germany. See Times 11 February 1814 and 7 April 1814.