Payment for hotel 6 months in advance

We are attending a family wedding in August, and are staying in the venue, a lovely country house hotel, on the night of the event. I was surprised to receive an email from the hotel, asking for payment now, 6 months ahead of the August date. A friend said the same had happened to them. Is this standard procedure now? If everyone pays early, the hotel have our money for 6 months! I would be happy to pay a deposit, but not the whole amount so far in advance. They do say we can cancel up to 24 hours before the event for a full refund, but I still think it's a cheek!