Reasonable fee to charge for permission to publish image in book?

[xarqi]

I've been approached by an agent searching for images for inclusion in a major work entitled "Life" who wishes to use one of my NZ native orchid pics - see below.

The offer is £20 (GBP) for the publication, and for the right to store the image in a database and use it in any future publication.

My first reaction was that I was happy enough about use in the single publication, but less so about the ongoing licence, and I've told them this.

What do you people on the front-line advise?

Here's the image, reduced and compressed. The original is from my 30D (8 mpix) and I have the RAW file.

[xarqi]

Update:
I had a reply from the agent to say that the project budget would not allow for more to be paid.

I've countered with an offer to license their perpetual usage of a smaller 400 x 533 pixel version, unmodified except for minor retouching, scaling, cropping, etc for their £20. It seemed like a decent compromise to me.

[Tom Reichner]

Update:
I had a reply from the agent to say that the project budget would not allow for more to be paid.

I've countered with an offer to license their perpetual usage of a smaller 400 x 533 pixel version, unmodified except for minor retouching, scaling, cropping, etc for their £20. It seemed like a decent compromise to me.

Yes, that does seem reasonable.

What I think is even more important than limiting the size at which they use the image is to limit how often they use the image. One-time publishing rights are the norm for this type of use (when a royalty-free license is used), so it seems odd that they include the language about using the image for any future publications. That seems odd to me that they would say that. I wonder if they know full well what is "normal" in the industry, but are just being petty with you to try to get a little bit more for their 20 pounds.