Our Qantas return flight to London last month was cancelled because of the volcanic ash situation and we were forced to spend an extra 2 weeks in Sydney, waiting for another flight. This involved us in a not inconsiderable expenditure for accommodation and subsistence.
On our return to the UK I submitted a claim to Qantas by email, more in hope than expectation, and was delighted to receive an email yesterday telling me my claim had been approved in full (all bar $40) and that my money would be refunded via my credit card.
So, well done Qantas and thank you. Good on yer!