The one problem with Saga Bonus miles from FI is that they expire at the end of three years, even if you fly within that time and accumulate more miles. If the miles stayed put, I'd have more than enough to fly Business Class from LHR, but the miles keep dropping out.....
When booking some fares at icelandair.co.uk the T&Cs will claim that the fares aren't eligible for miles, but then they've always posted to my account after the trip

- the same thing has happened with domestic Air Iceland flights. That makes up (a bit) for the miles stale-dating.
I'd never scorn anyone who had good things to say about Iceland, Knaldskalle!