Knee-high vs. ankle. Crunchy vs. smooth. Cheryl vs. Dannii.

In a world of agonizingly tough decisions, forgive us for offering one more.

Atop the former Dickins & Jones department store, Aqua London opens today. The first overseas outpost for the Hong Kong-based restaurant group is divided into two dining experiences, spread across a dizzying 17,000 square feet.

The first — Aqua Nueva (signposted by a giant bull) — serves contemporary Spanish fayre such as cockles and Iberian beef tenderloin with salsa. The second: Aqua Kyoto opens next week. There you can expect Japanese cuisine, from fresh sushi to dishes such as hamachi no kama (salt-grilled yellowtail collar) cooked over charcoal.

Both restaurants have huge year-round terraces with views over Central London. There’s also a bar for pre- and postdinner drinks. Prepare to be overwhelmed.

In fact, you’ll see double.

Aqua London, 240 Regent Street, entrance at 30 Argyll Street, W1F 7EB (020 7478 0540 or aqua-london.com).

Photo: Courtesy of Aqua London