Contacted by Rex Features about an image, are they reputable?

I was recently contacted by a editor from Rex Features, an "independent photographic press agency in the United Kingdom" about an image of mine they saw on PhotoPortfolios.net. They asked if I would be interested in having them try to "get it published in newspapers and magazines around the world" and "can offer 50% of any sales from images used in publications worldwide." They stated that they would require hi-res files of all the images in the set and any information I could provide about the particular image.

Has anybody heard of this company? I haven't e-mailed them back yet, but they said if I had any questions feel free to ask and that they understand that this request may be "out of the ordinary."

They are fine a very old established British company.
They are starting to search the web for interesting photos
Not being an American co. is why you havent heard of them.
Check out there website www.rexfeatures.com
AVI

I also was contacted by them to syndicate some of my images. They are an established agency, but I think they are on a microstock type hunt. I talked with them some, and I soon as I mentioned rights managed and wanting to know where and the extent of publications....I never heard from them again. Even after a couple of emails, they would not repond. I never even mentioned money or fees. I think they are looking for cheap images they will be able to use at their whim without restrictions. Proceed with caution.