Not entirely true. Passengers are always due a "duty of care" regardless of whether the reason for the delay is an "extraordinary circumstance". EC 261/2004 does not specify how much is due, but GBP 10 sounds a little bit on the low side, presuming that OP did not have lounge access. If OP had other expenses, he could submit his receipts and ask that they be reimbursed.

The weather argument seems pointless. On what facts is OP relying for his assertion?