Given that they are splashing out on a new HQ & paying out substantial dividends to shareholders, there is no excuse not to refund. Can't say - sorry we are legally obliged to pay the dividends and then say we are not paying the legally obliged refunds. Just make it "easy" to refund and cut the hassle. The Aer Lingus idea of voucher +10% & 5 years is a good option - for those that want it.
I'm in similar situation with TAP who are currently refusing any refunds - only vouchers and only for 12 months.