A speedy seafood stew

I really like things with fish and fresh seafood, but due to the dearth of fishmongers in the area my choice of ingredients is often limited to what is in the supermarket. Those plastic trays of prawns and mixed seafood aren't always the most inspiring thing, but I have realised that they can work very well in dishes like this. It's a vaguely Mediterranean concoction of fennel, olives, garlic and tomatoes, that is very tasty and quick enough to prepare for a post-work dinner.

Recipe (enough for 2 greedy people, with leftovers for the next day)

1 large bulb of fennel, finely sliced
1 small white onion, finely sliced
3 fat cloves of garlic, crushed
1 large sprig of thyme
1 tin chopped tomatoes (400g)
4 medium fresh tomatoes, roughly chopped or 1 heaped tsp tomato puree
Some water
About 15 small-ish green olives
1 tray mixed seafood, including squid and mussels (around 290g)
1 tray cooked king prawns (around 200g)
1/2 tsp chilli flakes
3 or 4 tblsp olive oil, or enough to generous coat the bottom of your cooking pan
Salt and pepper for seasoning

Heat the olive oil in reasonably large pan, and when it's warm put in the onion and fennel. Cook for around 5minutes over a medium-low heat until they've started to soften but not coloured. Then add the garlic, thyme and chilli flakes and cook for a few more minutes. Next, add the fresh tomato (or puree), the tin of tomatoes, and about half a tin's worth of water so that you have a loose tomato sauce. Simmer this on a low heat for about 10mins. At the end of this, the fennel should be tender. Next add the olives, and after another 5mins of simmering put in the cooked seafood. Add enough salt and pepper to season, and let the seafood heat through for a few minutes. Serve while piping hot with some bread.