Slightly interesting update as follows,
I take back my comment about their customer service being poor. I just called them again and got through to an extremely pleasant and helpful person there. Explained the situation and she immediately offered either a refund or (amazingly) to be put back onto the original flight. I explained I'd already called them a week ago to ask to be put back onto the original flight but was told that wasn't possible as it was no longer scheduled to fly even though I'd told the original person I spoke to that I was still able to use their website to book a seat on the original flight. That extra info promoted her to need to speak to her supervisor and listen to the tape of the call. She called me back 10 minutes later as promised (that alone is rare nowadays - for any customer service!) and said she would process the refund straight away (but for my interest their normal policy would not have been to give a refund, but instead to reinstate me on the original flight, but they could see that wasn't appropriate in this case as I'd been miss-advised on the first call to them).
Massive shame for all concerned. They were clearly still happy and able to fly me out there on the flight that had worked for me. I was happy to try economy class out at a fantastic price of just the £450 I paid originally. But I'd already deemed them poor and unable to help based on the first call to them and booked tickets with Emirates at £3k each instead (biz class instead so not a fair price comparison but the economy Ines were about £1000 I think).
Despite the better subsequent experience with them, I can't see me giving them a second chance booking with them again - seems too much down to luck whether it's good or poor with them.