Possible Clues:

• Large tasty flatfish
• It starts with Henry the First, although it's more than a little fishy
• Henry the First, although that's flat
• This may do for Henry I, but it's a large flat
• Will this do for Henry 1, although is very fishy?
• Seems to be Henry I, although that's very fishy
• This might be for Henry the First, although it's such a large flat
• It's largely flat, although it follows Henry the First
• Henry the First, perhaps, although that's flat
• Henry the First, in short, although that's fishy to a large extent