WooCommerce Bookings Reserve Days

Hi. I’m trying to create a plugin that will keep certain date ranges unavailable for logged out users, so only logged in users will be able to see the dates as available. I’ve tried using the filter hook ‘woocommerce_booking_get_availability_rules’ to alter the availability of the date range depending on if the user is logged in but this sometimes results in the whole day being shown as booked up when there is only one booking, plus when selecting some dates, it shows ‘Sorry, the selected block is not available’. Any ideas? Many thanks.