Incorrect on both counts I'm afraid.

261/2004 came into effect in February 2005. Compensation for delays of 3 hours or more wasn't part of the original Reg but was brought in via the Sturgeon ECJ judgment in 2009. This allows passengers to bring claims up to 6 years after the delayed flight in Eng/Wales, 5 years in Scotland.

The UK Court of Appeal ruled in the last 3 weeks on 2 relevant cases:

Dawson v Thomson where the airline were attempting to limit legal claims to 2 years only (rather than 6 years);

Huzar v Jet2.com where the airline claimed that unforeseeable or unexpected technical faults were extraordinary circumstances and therefore compensation should not be paid.

Both airlines lost their appeals and, although the CoA ruled that they had no right of appeal to the UK Supreme Court, they have both stated their intentions of petitioning the SC for leave to appeal. In the meantime the CoA judgments stand as precedent case law.