Compensation for cancelled / delayed flight

[BoggiesBonnieBelle]

DH and I were booked to fly to Australia. We were booked to fly from our local airport to Heathrow, Heathrow to Singapore, Singapore to Sydney, Sydney to Canberra.
We had opted for a 4pm flight from our local airport, and dinner at Heathrow as the next flight would be cutting it fine.

BA cancelled the 4pm flight, bumped us onto the 6pm, the 6pm was delayed, we missed our connection and were given overnight accomodation in Heathrow. BA rebooked us onto a Singapore Airlines airline, with a very tight connection at Singapore. We missed that connection too. We were rebooked onto another flight to Sydney and given overnight accommodation in Sydney. At Sydney we were also told that our luggage had gone missing, although it did turn up a few hours later. We got to Canberra 24 hours late.

BA are now saying that we are not entitled to compensation, because the 4pm flight was cancelled due to "bad weather" However, Flybe had a 4.15 flight to Heathrow, and it wasn't cancelled. They are also saying that although we were originally booked to fly BA from Heathrow to Singapore, once they had rebooked us onto a Singapore Airlines flight, they ceased to be responsible.

Can BA blame "bad weather" when other airlines were able to make the same flight? (Not disputing that it was raining at Heathrow).
Does rebooking us onto Singapore airlines mean they cease to be responsible?

Also, we booked our flights through a travel agent - should we go back to the travel agent and ask if they can help?

Maybe the bad weather meant that there was reduced capacity at the airport, which explains why some flights went and some were cancelled?

It's hard to say whether you are due compensation because the weather is outside the airline's control so would mean you weren't due compensation, but you might be able to claim for the delay on your travel insurance.

Also, as the problems that happened in Singapore onwards were outside the EU and on a non EU airline, then you can't claim on the EU261 or whatever it is.

One way to get compensation is to use the Moneysavingexpert resolver tool, it's free, so it could be worth a try, but I'm not sure that you are entitled in this case.

www.moneysavingexpert.com/site/resolver/

Also, as the problems that happened in Singapore onwards were outside the EU and on a non EU airline, then you can't claim on the EU261 or whatever it is.

So, because we were originally booked to fly BA from Heathrow to Singapore, but BA transferred us to Singapore Airlines, we lost any rights we had with BA?

That's annoying, and doesn't seem fair.

I am massively unimpressed with BA. If we'd booked the flight to Heathrow with one of the budget airlines, we'd have been fine, but we thought BA were the better quality option as it was such a long flight and we didn't want anything to go wrong.

The accommodation we were given at Heathrow was nice, but we were given one overnight pack to share between us i.e. one toothbrush between two, as a married couple. Fortunately we both had a toothbrush in our carry-on and didn't have to share.