Room tariff keeps changing

Hi all, I’m looking at booking a weekend away in November at a 5* hotel - problem is the room rate on their website keeps changing every few days… It’s gone +£30 and -£25 in the last week alone. What’s going on with this? I don’t know if I should wait longer to book to save more money or just bite the bullet now whilst it’s a slightly better price?

Could I book today and then claim a refund for the difference if the price reduces again? I wouldn’t normally be this bothered about saving a few quid but when you’re spending £400+ for one night away I want to get the best price I can