How to send a Mother's Day card to UK when Poczta Polska won't accept International deliveries?

Do any couriers send letters (as opposed to parcels) for a reasonable price? Any help appreciated

It would be better to send something from within the UK using a site like Interflora. It wouldn't cost that much for a small bunch of flowers or other Mother's Day gifty type thing. Possibly less than sending a letter via a courier.

Thanks..that's good thinking