Interesting about IDA, I hadn't realised that was the case. I assume that is a result of Brexit and means that they are no longer regulated by the FCA, however being from the UK I can still be covered by them?
I currently have an annual family DAN policy this is in addition to travel insurance provided by my bank account. Seems to work for me, although I haven't had to claim.
I did have to cancel a trip last year - my wife broke her leg a few weeks before an Egyptian liveaboard and wasn't allowed to fly. At the time we had travel cover from Staysure and they were pretty good to deal with. It took a couple of weeks but we got a full refund of flights and liveaboard costs, less a fairly small excess.
I have used Westfield in the past and found them very good to deal with (and they are based close to where I live), but their prices for annual family cover is way too high compared to other offerings, so doesn't work for me anymore.