I'm looking to buy a external flash for my nikon d5200 - any recommendations?

I'm looking to buy an external flash for my nikon d5200 on a budget of up to £250, any recommendations?

I would go on ebay

Check the seller's feedback up

If you are looking for a remote flash that attaches to the camera's hot shoe, the fine SB700 is within your budget.

However, if you want a flash that wirelessly is connected to the camera, you have to buy a SU800 commander (remote controller) along with the SB700.

I don't generally recommend the SB300 or SB400 for DSLRs as they are not that much more powerful than what the camera already has in the built-in flash. The SB300 especially is more adept to the Nikon P7700/P7800 series cameras.

March to the camera store and buy the meanest looking Nikon compatible flash you can afford. If you don't know what you're doing, ask for one that has full TTL compatibility with your camera. Bring your camera so that you can test the flash before paying for it.

Go for the Nikon SB700.It will give you more power and adjustability than lower models. For doing bounce flash, you will want that.
There are cheaper brands. Some reviewers are very happy with theirs, but there are many who have found them disappointing.